build: bump version to 0.6.3

an attempt to make it so that fixes like
fc6063dba8 never have to occur again

.config/nextest.toml

@@ -68,6 +68,10 @@ test-group = "serial-env-tests"
 filter = "package(tranquil-signal)"
 test-group = "serial-env-tests"
 
+[[profile.default.overrides]]
+filter = "package(tranquil-config)"
+test-group = "serial-env-tests"
+
 [[profile.default.overrides]]
 filter = "binary(whole_story)"
 test-group = "heavy-load-tests"
@@ -118,6 +122,10 @@ test-group = "serial-env-tests"
 filter = "package(tranquil-signal)"
 test-group = "serial-env-tests"
 
+[[profile.ci.overrides]]
+filter = "package(tranquil-config)"
+test-group = "serial-env-tests"
+
 [[profile.ci.overrides]]
 filter = "binary(whole_story)"
 test-group = "heavy-load-tests"

.gitignore

@@ -4,3 +4,5 @@ target/
 result
 frontend/node_modules/
 frontend/dist/
+frontend/.pnpm-store
+frontend/.npmrc

.sqlx/query-18bbda5582db1b32d02ab8a3eee970c9508b9bd67239c2f936639a9f863b30ff.json

@@ -1,6 +1,6 @@
 {
   "db_name": "PostgreSQL",
-  "query": "SELECT id, did, handle, email, created_at, deactivated_at, takedown_ref, is_admin\n               FROM users WHERE did = $1",
+  "query": "SELECT id, did, handle, email, created_at, deactivated_at, takedown_ref, is_admin, inbound_migration\n               FROM users WHERE handle = $1",
   "describe": {
     "columns": [
       {
@@ -42,6 +42,11 @@
         "ordinal": 7,
         "name": "is_admin",
         "type_info": "Bool"
+      },
+      {
+        "ordinal": 8,
+        "name": "inbound_migration",
+        "type_info": "Bool"
       }
     ],
     "parameters": {
@@ -57,8 +62,9 @@
       false,
       true,
       true,
+      false,
       false
     ]
   },
-  "hash": "6b51995c40519a63f85c70f29ca8bd6ec1963c8562d78215d980785dc46a6384"
+  "hash": "18bbda5582db1b32d02ab8a3eee970c9508b9bd67239c2f936639a9f863b30ff"
 }

.sqlx/query-23201d4e26bc650939e30f69fb0bca00d351d057098afebc1017f70a84b4bd22.json

@@ -1,14 +0,0 @@
-{
-  "db_name": "PostgreSQL",
-  "query": "UPDATE users SET deactivated_at = NULL WHERE did = $1",
-  "describe": {
-    "columns": [],
-    "parameters": {
-      "Left": [
-        "Text"
-      ]
-    },
-    "nullable": []
-  },
-  "hash": "23201d4e26bc650939e30f69fb0bca00d351d057098afebc1017f70a84b4bd22"
-}

.sqlx/query-51e029e572777e6a103fd7fd5550494de9d4cac7e3ff84e27ddec1a6aaefc047.json

@@ -0,0 +1,14 @@
+{
+  "db_name": "PostgreSQL",
+  "query": "UPDATE users SET deactivated_at = NULL, inbound_migration = FALSE WHERE did = $1",
+  "describe": {
+    "columns": [],
+    "parameters": {
+      "Left": [
+        "Text"
+      ]
+    },
+    "nullable": []
+  },
+  "hash": "51e029e572777e6a103fd7fd5550494de9d4cac7e3ff84e27ddec1a6aaefc047"
+}

.sqlx/query-5bee4ed5296667e4ca7e1a97aec28d30a470b8aee7b378ec9ca4e34de4faf349.json

@@ -0,0 +1,15 @@
+{
+  "db_name": "PostgreSQL",
+  "query": "UPDATE comms_queue\n               SET status = 'failed'::comms_status,\n                   attempts = max_attempts,\n                   last_error = $2,\n                   updated_at = NOW()\n               WHERE id = $1",
+  "describe": {
+    "columns": [],
+    "parameters": {
+      "Left": [
+        "Uuid",
+        "Text"
+      ]
+    },
+    "nullable": []
+  },
+  "hash": "5bee4ed5296667e4ca7e1a97aec28d30a470b8aee7b378ec9ca4e34de4faf349"
+}

.sqlx/query-890aa92acdcb0fe2a3bf04d87e1f16a801d271da7cedc32fc42c2ef5b100faae.json

@@ -1,6 +1,6 @@
 {
   "db_name": "PostgreSQL",
-  "query": "UPDATE comms_queue\n               SET status = 'processing', updated_at = NOW()\n               WHERE id IN (\n                   SELECT id FROM comms_queue\n                   WHERE status = 'pending'\n                     AND scheduled_for <= $1\n                     AND attempts < max_attempts\n                   ORDER BY scheduled_for ASC\n                   LIMIT $2\n                   FOR UPDATE SKIP LOCKED\n               )\n               RETURNING\n                   id, user_id,\n                   channel as \"channel: CommsChannel\",\n                   comms_type as \"comms_type: CommsType\",\n                   status as \"status: CommsStatus\",\n                   recipient, subject, body, metadata,\n                   attempts, max_attempts, last_error,\n                   created_at, updated_at, scheduled_for, processed_at",
+  "query": "UPDATE comms_queue\n               SET status = 'processing', updated_at = NOW()\n               WHERE id IN (\n                   SELECT id FROM comms_queue\n                   WHERE attempts < max_attempts\n                     AND scheduled_for <= $1\n                     AND (\n                         status = 'pending'\n                         OR (status = 'processing'\n                             AND updated_at < $1 - INTERVAL '10 minutes')\n                     )\n                   ORDER BY scheduled_for ASC\n                   LIMIT $2\n                   FOR UPDATE SKIP LOCKED\n               )\n               RETURNING\n                   id, user_id,\n                   channel as \"channel: CommsChannel\",\n                   comms_type as \"comms_type: CommsType\",\n                   status as \"status: CommsStatus\",\n                   recipient, subject, body, metadata,\n                   attempts, max_attempts, last_error,\n                   created_at, updated_at, scheduled_for, processed_at",
   "describe": {
     "columns": [
       {
@@ -154,5 +154,5 @@
       true
     ]
   },
-  "hash": "8047fda41bd94f819213decb8b3e0aba49a8dbdb10217eefd77e3567f8c9694a"
+  "hash": "890aa92acdcb0fe2a3bf04d87e1f16a801d271da7cedc32fc42c2ef5b100faae"
 }

.sqlx/query-8f4357f7a18ddcf6b686a4555f244d37c35917364b8f917ca6ee2d4030ace742.json

@@ -1,6 +1,6 @@
 {
   "db_name": "PostgreSQL",
-  "query": "\n            DELETE FROM oauth_token\n            WHERE id IN (\n                SELECT id FROM oauth_token\n                WHERE did = $1\n                ORDER BY updated_at ASC\n                OFFSET $2\n            )\n            ",
+  "query": "\n            DELETE FROM oauth_token\n            WHERE id IN (\n                SELECT id FROM oauth_token\n                WHERE did = $1\n                ORDER BY created_at DESC\n                OFFSET $2\n            )\n            ",
   "describe": {
     "columns": [],
     "parameters": {
@@ -11,5 +11,5 @@
     },
     "nullable": []
   },
-  "hash": "56cd24903171eddc2ededd9079ffe10937c34e99b0305f25c980ca754da44625"
+  "hash": "8f4357f7a18ddcf6b686a4555f244d37c35917364b8f917ca6ee2d4030ace742"
 }

.sqlx/query-f1c4ec28b02d09ffce35aa8249c1747a70c12a3ecfc1ff6ca1847840f770db2f.json

@@ -1,6 +1,6 @@
 {
   "db_name": "PostgreSQL",
-  "query": "SELECT id, did, handle, email, created_at, deactivated_at, takedown_ref, is_admin\n               FROM users WHERE handle = $1",
+  "query": "SELECT id, did, handle, email, created_at, deactivated_at, takedown_ref, is_admin, inbound_migration\n               FROM users WHERE did = $1",
   "describe": {
     "columns": [
       {
@@ -42,6 +42,11 @@
         "ordinal": 7,
         "name": "is_admin",
         "type_info": "Bool"
+      },
+      {
+        "ordinal": 8,
+        "name": "inbound_migration",
+        "type_info": "Bool"
       }
     ],
     "parameters": {
@@ -57,8 +62,9 @@
       false,
       true,
       true,
+      false,
       false
     ]
   },
-  "hash": "584bceda60d8b6a02e7dc44d833e3fba13151f36ba9f75c64e33d6cb534cc939"
+  "hash": "f1c4ec28b02d09ffce35aa8249c1747a70c12a3ecfc1ff6ca1847840f770db2f"
 }

.tangled/workflows/publish-cachix-aarch64.yml

@@ -18,4 +18,4 @@ steps:
   - name: Build and push aarch64
     command: |
       SUBS="--option extra-substituters https://tranquil.cachix.org --option extra-trusted-public-keys tranquil.cachix.org-1:PoO+mGL6a6LcJiPakMDHN4E218/ei/7v2sxeDtNkSRg="
-      nix-store -qR --include-outputs $(nix-store -qd $(nix build .#packages.x86_64-linux.tranquil-pds-aarch64 $SUBS --print-out-paths --no-link)) | grep -v '\.drv$' | cachix push "$CACHIX_CACHE_NAME"
+      nix-store -qR --include-outputs $(nix-store -qd $(nix build .#packages.x86_64-linux.tranquil-pds-aarch64 $SUBS --print-out-paths --no-link)) | grep -v '\.drv$' | cachix push tranquil

.tangled/workflows/publish-cachix-x86_64.yml

@@ -18,11 +18,11 @@ steps:
   - name: Build and push x86_64
     command: |
       SUBS="--option extra-substituters https://tranquil.cachix.org --option extra-trusted-public-keys tranquil.cachix.org-1:PoO+mGL6a6LcJiPakMDHN4E218/ei/7v2sxeDtNkSRg="
-      nix-store -qR --include-outputs $(nix-store -qd $(nix build .#packages.x86_64-linux.tranquil-pds $SUBS --print-out-paths --no-link)) | grep -v '\.drv$' | cachix push "$CACHIX_CACHE_NAME"
-      nix-store -qR --include-outputs $(nix-store -qd $(nix build .#packages.x86_64-linux.tranquil-frontend $SUBS --print-out-paths --no-link)) | grep -v '\.drv$' | cachix push "$CACHIX_CACHE_NAME"
+      nix-store -qR --include-outputs $(nix-store -qd $(nix build .#packages.x86_64-linux.tranquil-pds $SUBS --print-out-paths --no-link)) | grep -v '\.drv$' | cachix push tranquil
+      nix-store -qR --include-outputs $(nix-store -qd $(nix build .#packages.x86_64-linux.tranquil-frontend $SUBS --print-out-paths --no-link)) | grep -v '\.drv$' | cachix push tranquil
 
   - name: Build and push devShell
     command: |
       SUBS="--option extra-substituters https://tranquil.cachix.org --option extra-trusted-public-keys tranquil.cachix.org-1:PoO+mGL6a6LcJiPakMDHN4E218/ei/7v2sxeDtNkSRg="
       nix develop $SUBS --profile dev-profile -c true
-      cachix push "$CACHIX_CACHE_NAME" dev-profile
+      cachix push tranquil dev-profile

.tangled/workflows/publish-image.yml

@@ -1,24 +1,36 @@
 when:
-  - event: []
-    branch: []
+  - event: [ "manual" ]
+  - event: [ "push" ]
+    branch: [ "main" ]
 
 engine: nixery
 
 dependencies:
   nixpkgs:
-    - podman
+    - kaniko
+
+environment:
+  DOCKER_CONFIG: "/kaniko/.docker"
 
 steps:
-  - name: Create podman config
+  - name: Configure Kaniko
     command: |
-      mkdir -p ~/.config/containers
-      echo "unqualified-search-registries = [\"docker.io\"]" >> ~/.config/containers/registries.conf
+      mkdir -p /kaniko/.docker/
+      echo "{
+        \"auths\": {
+          \"https://atcr.io/v1\":{
+            \"auth\": \"$ATCR_CREDENTIALS\"
+          }
+        }
+      }" > /kaniko/.docker/config.json
 
   - name: Build image
     command: |
-      podman build . -t tranquil-pds:latest -t "tranquil-pds:$TANGLED_COMMIT_SHA"
-
-  - name: Publish image
-    command: |
-      podman push --creds "$ATCR_USERNAME:$ATCR_PASSWORD" tranquil-pds:latest "atcr.io/tranquil.farm/tranquil-pds:latest"
-      podman push --creds "$ATCR_USERNAME:$ATCR_PASSWORD" "tranquil-pds:$TANGLED_COMMIT_SHA" "atcr.io/tranquil.farm/tranquil-pds:$TANGLED_COMMIT_SHA"
+      executor \
+        --context=$(pwd) \
+        --ignore-path=$(pwd) \
+        --dockerfile=$(pwd)/Dockerfile \
+        --destination="atcr.io/tranquil.farm/tranquil-pds:latest" \
+        --destination="atcr.io/tranquil.farm/tranquil-pds:$TANGLED_COMMIT_SHA" \
+        --push-retry=3 \
+        --skip-push-permission-check

CONTRIBUTING.md

@@ -0,0 +1,135 @@
+# Contributing to Tranquil PDS
+
+## When PRing
+
+In order of importance:
+
+- **You must run your change! Every contribution that says "here's xyz. untested." does not help the project.**
+- Relevant tests to your PR must pass. The whole suite doesn't have to be proven to have run, because there are a *ton* of tests and they're quite heavy, but hopefully there are existing tests for whatever you're PRing, and if there aren't, please add those too.
+- Run cargo fmt :P
+
+> 🦪 Lewis
+>
+> Good CI fixes some of these. We should really get around to that.
+
+Things that would also be nice but aren't like, a pain in our side:
+
+- Big changes should be stacked PRs that are broken up into digestible pieces. Those stacked PRs should hopefully be able to be merged individually if necessary.
+
+## Local Development
+
+### Prerequisites
+
+- [Docker](https://docs.docker.com/get-docker/) and Docker Compose
+- Add `pds.test` to your hosts file (one-time setup):
+
+  ```
+  127.0.0.1 pds.test
+  ```
+
+  - **macOS / Linux:** `/etc/hosts`
+  - **Windows:** `C:\Windows\System32\drivers\etc\hosts`
+
+### Starting the dev environment
+
+```bash
+just run-dev
+```
+
+This starts the following services via `docker-compose`:
+
+- **Traefik** — HTTPS reverse proxy at `https://pds.test`
+- **Backend** — Rust server with `cargo-watch` (auto-rebuilds on file changes)
+- **Frontend** — Vite dev server with hot module replacement
+- **Postgres** — Database on port 5432
+- **PLC Directory** — Local [did-method-plc](https://github.com/did-method-plc/did-method-plc) server for DID registration
+- **Mailpit** — Local email server with web UI at [http://localhost:8025](http://localhost:8025)
+
+Once all services are running, open **https://pds.test** in your browser.
+
+### Trusting the self-signed certificate
+
+Traefik generates a self-signed TLS certificate. Your browser will show a security warning on first visit. You can either click through it, or add the certificate to your system trust store for a seamless experience:
+
+**macOS:**
+
+```bash
+# Extract the cert from traefik and add it to the system keychain
+echo | openssl s_client -connect localhost:443 -servername pds.test 2>/dev/null | openssl x509 > /tmp/pds-test.pem
+sudo security add-trusted-cert -d -r trustRoot -k /Library/Keychains/System.keychain /tmp/pds-test.pem
+```
+
+**Linux (Debian/Ubuntu):**
+
+```bash
+echo | openssl s_client -connect localhost:443 -servername pds.test 2>/dev/null | openssl x509 | sudo tee /usr/local/share/ca-certificates/pds-test.crt
+sudo update-ca-certificates
+```
+
+**Linux (Fedora/RHEL):**
+
+```bash
+echo | openssl s_client -connect localhost:443 -servername pds.test 2>/dev/null | openssl x509 | sudo tee /etc/pki/ca-trust/source/anchors/pds-test.pem
+sudo update-ca-trust
+```
+
+**Windows (PowerShell as Administrator):**
+
+```powershell
+$cert = New-Object System.Security.Cryptography.X509Certificates.X509Certificate2
+$cert.Import([System.Text.Encoding]::UTF8.GetBytes((echo | openssl s_client -connect localhost:443 -servername pds.test 2>$null | openssl x509)))
+$store = New-Object System.Security.Cryptography.X509Certificates.X509Store("Root", "LocalMachine")
+$store.Open("ReadWrite")
+$store.Add($cert)
+$store.Close()
+```
+
+Restart your browser after adding the certificate.
+
+### Stopping the dev environment
+
+```bash
+# Stop containers (preserves database + build cache)
+docker compose --profile dev down
+
+# Stop and wipe all data (fresh start)
+docker compose --profile dev down -v
+```
+
+### Direct database access
+
+Postgres is exposed on port 5432:
+
+```bash
+psql postgres://postgres:postgres@localhost:5432/pds
+```
+
+### How it works
+
+- **Source code** is bind-mounted into the containers so that changes made on the host will be immediately reflected in the application
+- **Backend** uses `cargo-watch` to recompile and restart when Rust files change
+- **Frontend** uses Vite's HMR for instant browser updates when frontend files change
+- **Build cache** (`target/` directory and cargo registry) are stored in Docker volumes, so incremental compilation persists across container restarts
+- **Traefik** routes `/`, `/xrpc`, `/oauth`, `/.well-known`, `/u`, and `/health` to the backend; everything else goes to the Vite dev server
+- **Mailpit** captures all outgoing email — open [http://localhost:8025](http://localhost:8025) to view verification emails during registration
+- **PLC Directory** runs locally so DID registration doesn't hit the real `plc.directory`
+
+### Running the backend natively
+
+If you prefer running the Rust backend outside Docker (faster incremental builds on host), you need:
+
+- Rust toolchain (see `rust-toolchain.toml`)
+- `protoc` (`brew install protobuf` on macOS)
+- PostgreSQL (start with `docker compose up db`)
+
+Then run:
+
+```bash
+cargo run -p tranquil-server -- --config config.toml
+```
+
+And start the frontend separately:
+
+```bash
+cd frontend && pnpm install && pnpm dev
+```

Cargo.lock

@@ -9,7 +9,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "087113bd50d9adce24850eed5d0476c7d199d532fce8fab5173650331e09033a"
 dependencies = [
  "abnf-core",
- "nom",
+ "nom 7.1.3",
 ]
 
 [[package]]
@@ -18,7 +18,7 @@ version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c44e09c43ae1c368fb91a03a566472d0087c26cf7e1b9e8e289c14ede681dd7d"
 dependencies = [
- "nom",
+ "nom 7.1.3",
 ]
 
 [[package]]
@@ -213,7 +213,7 @@ dependencies = [
  "asn1-rs-derive",
  "asn1-rs-impl",
  "displaydoc",
- "nom",
+ "nom 7.1.3",
  "num-traits",
  "rusticata-macros",
  "thiserror 1.0.69",
@@ -1972,7 +1972,7 @@ checksum = "5cd0a5c643689626bec213c4d8bd4d96acc8ffdb4ad4bb6bc16abf27d5f4b553"
 dependencies = [
  "asn1-rs",
  "displaydoc",
- "nom",
+ "nom 7.1.3",
  "num-bigint",
  "num-traits",
  "rusticata-macros",
@@ -2216,6 +2216,22 @@ dependencies = [
  "zeroize",
 ]
 
+[[package]]
+name = "email-encoding"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9298e6504d9b9e780ed3f7dfd43a61be8cd0e09eb07f7706a945b0072b6670b6"
+dependencies = [
+ "base64 0.22.1",
+ "memchr",
+]
+
+[[package]]
+name = "email_address"
+version = "0.2.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e079f19b08ca6239f47f8ba8509c11cf3ea30095831f7fed61441475edd8c449"
+
 [[package]]
 name = "embedded-io"
 version = "0.4.0"
@@ -3780,6 +3796,37 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "09edd9e8b54e49e587e4f6295a7d29c3ea94d469cb40ab8ca70b288248a81db2"
 
+[[package]]
+name = "lettre"
+version = "0.11.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dabda5859ee7c06b995b9d1165aa52c39110e079ef609db97178d86aeb051fa7"
+dependencies = [
+ "async-trait",
+ "base64 0.22.1",
+ "ed25519-dalek",
+ "email-encoding",
+ "email_address",
+ "fastrand",
+ "futures-io",
+ "futures-util",
+ "httpdate",
+ "idna",
+ "mime",
+ "nom 8.0.0",
+ "percent-encoding",
+ "quoted_printable",
+ "rsa",
+ "rustls 0.23.37",
+ "sha2",
+ "socket2 0.6.3",
+ "tokio",
+ "tokio-rustls 0.26.4",
+ "tracing",
+ "url",
+ "webpki-roots 1.0.6",
+]
+
 [[package]]
 name = "libc"
 version = "0.2.183"
@@ -4409,6 +4456,15 @@ dependencies = [
  "minimal-lexical",
 ]
 
+[[package]]
+name = "nom"
+version = "8.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "df9761775871bdef83bee530e60050f7e54b1105350d6884eb0fb4f46c2f9405"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "nonzero_ext"
 version = "0.3.0"
@@ -4839,7 +4895,7 @@ checksum = "9114f9c1683dd09c5f4fa024c89fdad783eaae21d3d52dd23ddaaffa29ffb168"
 dependencies = [
  "either",
  "fnv",
- "nom",
+ "nom 7.1.3",
  "once_cell",
  "postcard",
  "quick-xml",
@@ -5427,6 +5483,12 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "quoted_printable"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "478e0585659a122aa407eb7e3c0e1fa51b1d8a870038bd29f0cf4a8551eea972"
+
 [[package]]
 name = "r-efi"
 version = "5.3.0"
@@ -5833,7 +5895,7 @@ version = "4.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "faf0c4a6ece9950b9abdb62b1cfcf2a68b3b67a10ba445b3bb85be2a293d0632"
 dependencies = [
- "nom",
+ "nom 7.1.3",
 ]
 
 [[package]]
@@ -6050,6 +6112,16 @@ dependencies = [
  "zeroize",
 ]
 
+[[package]]
+name = "secrecy"
+version = "0.10.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e891af845473308773346dc847b2c23ee78fe442e0472ac50e22a18a93d3ae5a"
+dependencies = [
+ "serde",
+ "zeroize",
+]
+
 [[package]]
 name = "security-framework"
 version = "3.7.0"
@@ -7455,7 +7527,7 @@ dependencies = [
 
 [[package]]
 name = "tranquil-api"
-version = "0.5.6"
+version = "0.6.3"
 dependencies = [
  "anyhow",
  "axum",
@@ -7506,7 +7578,7 @@ dependencies = [
 
 [[package]]
 name = "tranquil-auth"
-version = "0.5.6"
+version = "0.6.3"
 dependencies = [
  "anyhow",
  "base32",
@@ -7529,7 +7601,7 @@ dependencies = [
 
 [[package]]
 name = "tranquil-cache"
-version = "0.5.6"
+version = "0.6.3"
 dependencies = [
  "async-trait",
  "base64 0.22.1",
@@ -7543,11 +7615,19 @@ dependencies = [
 
 [[package]]
 name = "tranquil-comms"
-version = "0.5.6"
+version = "0.6.3"
 dependencies = [
  "async-trait",
  "base64 0.22.1",
+ "chrono",
+ "ed25519-dalek",
+ "futures",
+ "hickory-resolver",
+ "lettre",
+ "rand 0.8.5",
  "reqwest",
+ "rsa",
+ "secrecy",
  "serde_json",
  "sqlx",
  "thiserror 2.0.18",
@@ -7561,7 +7641,7 @@ dependencies = [
 
 [[package]]
 name = "tranquil-config"
-version = "0.5.6"
+version = "0.6.3"
 dependencies = [
  "confique",
  "serde",
@@ -7569,7 +7649,7 @@ dependencies = [
 
 [[package]]
 name = "tranquil-crypto"
-version = "0.5.6"
+version = "0.6.3"
 dependencies = [
  "aes-gcm",
  "base64 0.22.1",
@@ -7585,7 +7665,7 @@ dependencies = [
 
 [[package]]
 name = "tranquil-db"
-version = "0.5.6"
+version = "0.6.3"
 dependencies = [
  "async-trait",
  "chrono",
@@ -7602,7 +7682,7 @@ dependencies = [
 
 [[package]]
 name = "tranquil-db-traits"
-version = "0.5.6"
+version = "0.6.3"
 dependencies = [
  "async-trait",
  "base64 0.22.1",
@@ -7618,7 +7698,7 @@ dependencies = [
 
 [[package]]
 name = "tranquil-infra"
-version = "0.5.6"
+version = "0.6.3"
 dependencies = [
  "async-trait",
  "bytes",
@@ -7629,7 +7709,7 @@ dependencies = [
 
 [[package]]
 name = "tranquil-lexicon"
-version = "0.5.6"
+version = "0.6.3"
 dependencies = [
  "chrono",
  "futures",
@@ -7648,7 +7728,7 @@ dependencies = [
 
 [[package]]
 name = "tranquil-oauth"
-version = "0.5.6"
+version = "0.6.3"
 dependencies = [
  "anyhow",
  "axum",
@@ -7671,7 +7751,7 @@ dependencies = [
 
 [[package]]
 name = "tranquil-oauth-server"
-version = "0.5.6"
+version = "0.6.3"
 dependencies = [
  "axum",
  "base64 0.22.1",
@@ -7704,7 +7784,7 @@ dependencies = [
 
 [[package]]
 name = "tranquil-pds"
-version = "0.5.6"
+version = "0.6.3"
 dependencies = [
  "aes-gcm",
  "anyhow",
@@ -7744,6 +7824,7 @@ dependencies = [
  "multibase",
  "multihash",
  "p256 0.13.2",
+ "parking_lot",
  "rand 0.8.5",
  "redis",
  "regex",
@@ -7796,7 +7877,7 @@ dependencies = [
 
 [[package]]
 name = "tranquil-repo"
-version = "0.5.6"
+version = "0.6.3"
 dependencies = [
  "bytes",
  "cid",
@@ -7808,7 +7889,7 @@ dependencies = [
 
 [[package]]
 name = "tranquil-ripple"
-version = "0.5.6"
+version = "0.6.3"
 dependencies = [
  "async-trait",
  "backon",
@@ -7833,7 +7914,7 @@ dependencies = [
 
 [[package]]
 name = "tranquil-scopes"
-version = "0.5.6"
+version = "0.6.3"
 dependencies = [
  "axum",
  "futures",
@@ -7849,15 +7930,24 @@ dependencies = [
 
 [[package]]
 name = "tranquil-server"
-version = "0.5.6"
+version = "0.6.3"
 dependencies = [
+ "arc-swap",
  "axum",
  "clap",
  "dotenvy",
  "ed25519-dalek",
+ "futures-util",
  "hex",
+ "hyper 1.8.1",
+ "hyper-util",
+ "rustls 0.23.37",
+ "rustls-pemfile",
+ "thiserror 2.0.18",
  "tokio",
+ "tokio-rustls 0.26.4",
  "tokio-util",
+ "tower",
  "tracing",
  "tracing-subscriber",
  "tranquil-api",
@@ -7870,7 +7960,7 @@ dependencies = [
 
 [[package]]
 name = "tranquil-signal"
-version = "0.5.6"
+version = "0.6.3"
 dependencies = [
  "async-trait",
  "chrono",
@@ -7893,7 +7983,7 @@ dependencies = [
 
 [[package]]
 name = "tranquil-storage"
-version = "0.5.6"
+version = "0.6.3"
 dependencies = [
  "async-trait",
  "aws-config",
@@ -7910,7 +8000,7 @@ dependencies = [
 
 [[package]]
 name = "tranquil-store"
-version = "0.5.6"
+version = "0.6.3"
 dependencies = [
  "async-trait",
  "bytes",
@@ -7959,7 +8049,7 @@ dependencies = [
 
 [[package]]
 name = "tranquil-sync"
-version = "0.5.6"
+version = "0.6.3"
 dependencies = [
  "anyhow",
  "axum",
@@ -7981,7 +8071,7 @@ dependencies = [
 
 [[package]]
 name = "tranquil-types"
-version = "0.5.6"
+version = "0.6.3"
 dependencies = [
  "chrono",
  "cid",
@@ -8496,7 +8586,7 @@ dependencies = [
  "base64urlsafedata",
  "der-parser",
  "hex",
- "nom",
+ "nom 7.1.3",
  "openssl",
  "openssl-sys",
  "rand 0.9.2",
@@ -9068,7 +9158,7 @@ dependencies = [
  "data-encoding",
  "der-parser",
  "lazy_static",
- "nom",
+ "nom 7.1.3",
  "oid-registry",
  "rusticata-macros",
  "thiserror 1.0.69",

Cargo.toml

@@ -26,7 +26,7 @@ members = [
 ]
 
 [workspace.package]
-version = "0.5.6"
+version = "0.6.3"
 edition = "2024"
 license = "AGPL-3.0-or-later"
 
@@ -59,6 +59,7 @@ presage = { git = "https://github.com/whisperfish/presage", rev = "fe3ed54c4844a
 unicode-segmentation = "1"
 
 aes-gcm = "0.10"
+arc-swap = "1"
 backon = "1"
 bincode = { version = "2", features = ["serde"] }
 anyhow = "1.0"
@@ -86,6 +87,8 @@ hickory-resolver = { version = "0.24", features = ["tokio-runtime"] }
 hkdf = "0.12"
 hmac = "0.12"
 http = "1.4"
+hyper = { version = "1", features = ["server", "http1", "http2"] }
+hyper-util = { version = "0.1", features = ["server", "server-auto", "server-graceful", "service", "tokio"] }
 image = { version = "0.25", default-features = false, features = ["jpeg", "png", "gif", "webp"] }
 qrcodegen = "1.8"
 infer = "0.19"
@@ -93,6 +96,7 @@ ipld-core = "0.4"
 iroh-car = "0.5"
 jacquard-common = { version = "0.9", features = ["crypto-k256"] }
 jacquard-repo = "0.9"
+lettre = { version = "0.11", default-features = false, features = ["builder", "smtp-transport", "tokio1", "tokio1-rustls-tls", "pool", "dkim", "tracing"] }
 jsonwebtoken = { version = "10.2", features = ["rust_crypto"] }
 k256 = { version = "0.13", features = ["ecdsa", "pem", "pkcs8"] }
 metrics = "0.24"
@@ -105,6 +109,10 @@ p384 = { version = "0.13", features = ["ecdsa"] }
 rand = "0.8"
 redis = { version = "1.0", features = ["tokio-comp", "connection-manager"] }
 regex = "1"
+rsa = "0.9"
+rustls = { version = "0.23", default-features = false, features = ["ring", "std", "tls12", "logging"] }
+rustls-pemfile = "2"
+secrecy = { version = "0.10", features = ["serde"] }
 reqwest = { version = "0.12", default-features = false, features = ["json", "rustls-tls-webpki-roots", "http2", "charset", "macos-system-configuration"] }
 serde = { version = "1.0", features = ["derive"] }
 serde_bytes = "0.11"
@@ -116,8 +124,9 @@ sqlx = { version = "0.8", features = ["runtime-tokio-rustls", "postgres", "uuid"
 subtle = "2.5"
 thiserror = "2.0"
 tokio = { version = "1.48", features = ["macros", "rt-multi-thread", "time", "signal", "process", "io-util", "fs"] }
-tokio-util = "0.7.18"
+tokio-util = { version = "0.7.18", features = ["rt"] }
 tokio-tungstenite = { version = "0.28", features = ["rustls-tls-webpki-roots"] }
+tokio-rustls = { version = "0.26", default-features = false, features = ["ring", "tls12", "logging"] }
 totp-rs = { version = "5", features = ["qr"] }
 tower = "0.5"
 tower-http = { version = "0.6", features = ["fs", "cors"] }

Dockerfile

@@ -1,7 +1,7 @@
 FROM node:24-alpine AS frontend
 RUN corepack enable && corepack prepare pnpm@latest --activate
 WORKDIR /app
-COPY frontend/package.json frontend/pnpm-lock.yaml ./
+COPY frontend/package.json frontend/pnpm-lock.yaml frontend/pnpm-workspace.yaml ./
 RUN pnpm install --frozen-lockfile
 COPY frontend/ ./
 RUN pnpm build
@@ -35,7 +35,7 @@ COPY crates/tranquil-oauth-server ./crates/tranquil-oauth-server
 COPY crates/tranquil-store ./crates/tranquil-store
 COPY crates/tranquil-signal ./crates/tranquil-signal
 COPY crates/tranquil-server ./crates/tranquil-server
-COPY migrations ./crates/tranquil-pds/migrations
+COPY migrations ./migrations
 RUN --mount=type=cache,target=/usr/local/cargo/registry \
     --mount=type=cache,target=/app/target \
     if [ "$SLIM" = "true" ]; then \
@@ -46,13 +46,11 @@ RUN --mount=type=cache,target=/usr/local/cargo/registry \
     cp target/release/tranquil-server /tmp/tranquil-pds
 
 FROM alpine:3.23
-RUN apk add --no-cache msmtp ca-certificates \
-    && ln -sf /usr/bin/msmtp /usr/sbin/sendmail
+RUN apk add --no-cache ca-certificates
 COPY --from=builder /tmp/tranquil-pds /usr/local/bin/tranquil-pds
 COPY --from=frontend /app/dist /var/lib/tranquil-pds/frontend
-COPY migrations /app/migrations
 WORKDIR /app
-ENV SERVER_HOST=0.0.0.0
+ENV SERVER_HOST=[::]
 ENV SERVER_PORT=3000
 EXPOSE 3000
 CMD ["tranquil-pds"]

Dockerfile.dev

@@ -0,0 +1,20 @@
+FROM rust:1.92-alpine
+
+RUN apk add --no-cache \
+    ca-certificates \
+    musl-dev \
+    pkgconfig \
+    openssl-dev \
+    openssl-libs-static \
+    mold \
+    clang \
+    protoc
+
+RUN cargo install cargo-watch
+
+ENV RUSTFLAGS="-C linker=clang -C link-arg=-fuse-ld=mold"
+ENV SQLX_OFFLINE=true
+
+WORKDIR /app
+
+CMD ["cargo", "watch", "-x", "run -p tranquil-server -- --config /app/config.dev.toml"]

README.md

@@ -6,7 +6,7 @@ A Personal Data Server for the AT Protocol.
 
 We came together to make this PDS to enable and empower our users to better host their data on this shared protocol. All of our decisions as a project are guided by their usefulness to the community: PDS hosters and end-users both. 
 
-Comparatively: Bluesky the company created a "reference PDS" that we can self-host quite easily, and that's great, but Bluesky has an incentive to make software for themselvess first & foremost, then secondly their software can be useful for us self-hosters. In contrast, Tranquil is not from a company, and will never be.
+Comparatively: Bluesky the company created a "reference PDS" that we can self-host quite easily, and that's great, but Bluesky has an incentive to make software for themselves first & foremost, then secondly their software can be useful for us self-hosters. In contrast, Tranquil is not from a company, and will never be.
 
 ## What's different about Tranquil PDS
 
@@ -20,7 +20,7 @@ It is a superset of the reference PDS, including:
 - account delegation: letting others manage an account with configurable permission levels
 - a built-in web UI for account management, repo browsing, and admin
 
-Unlike the ref PDS, Tranquil itself is compiled to a single binary with no nodeJS runtime. However, at time of writing, Tranquil requires postgres running separately.
+Unlike the ref PDS, Tranquil is a single binary with no nodejs runtime. That said, at time of writing, Tranquil does require postgres running separately.
 
 ## Quick Start
 
@@ -46,25 +46,28 @@ just test
 just lint
 ```
 
-Nix users can enter a devshell with `nix develop`, or `direnv allow` to auto-enter via the bundled `.envrc`. Pre-built artifacts (including the devshell) are available from our [binary cache](docs/install-nix.md#binary-cache).
+Nix users can enter a devshell with `nix develop`, or `direnv allow` to auto-enter via the bundled `.envrc`. Pre-built artifacts including the devshell are available from our [binary cache](docs/2_INSTALL_NIX.md#binary-cache).
 
 ## Production Deployment
 
 ### Quick Deploy (Docker/Podman Compose)
 
-Edit `config.toml` with your values. Generate secrets with `openssl rand -base64 48`.
+`docker-compose.prod.yaml` pulls the prebuilt image `atcr.io/tranquil.farm/tranquil-pds:latest`. Sign in to the registry first with `podman login atcr.io`. The Containers guide covers building from source.
 
 ```bash
 cp example.toml config.toml
+```
+
+Edit `config.toml` with your values and generate secrets with `openssl rand -base64 48`. Set the postgres password to match `docker-compose.prod.yaml`. nginx needs a TLS certificate before it starts, so follow the wildcard cert steps in the [Containers guide](docs/2_INSTALL_CONTAINERS.md).
+
+```bash
 podman-compose -f docker-compose.prod.yaml up -d
 ```
 
 ### Installation Guides
 
-- [Nix](docs/install-nix.md)
-- [Debian](docs/install-debian.md)
-- [Containers](docs/install-containers.md)
-- [Kubernetes](docs/install-kubernetes.md)
+- [Nix](docs/2_INSTALL_NIX.md)
+- [Containers](docs/2_INSTALL_CONTAINERS.md)
 
 ## Community
 
@@ -77,7 +80,7 @@ We currently don't have a shared space to chat and organize Tranquil things, but
 - [@oyster.cafe](https://tangled.org/did:plc:3fwecdnvtcscjnrx2p4n7alz)
 - [@nel.pet](https://tangled.org/did:plc:h5wsnqetncv6lu2weom35lg2)
 
-### Amazing contributers
+### Amazing contributors
 
 - [@isabelroses.com](https://tangled.org/did:plc:qxichs7jsycphrsmbujwqbfb)
 - [@quilling.dev](https://tangled.org/did:plc:jrtgsidnmxaen4offglr5lsh)
@@ -88,6 +91,7 @@ We currently don't have a shared space to chat and organize Tranquil things, but
 - [@a.starrysky.fyi](https://tangled.org/did:plc:uuyqs6y3pwtbteet4swt5i5y)
 - [@sans-self.org](https://tangled.org/did:plc:wydyrngmxbcsqdvhmd7whmye)
 - [@tachyonism.tngl.sh](https://tangled.org/did:plc:w6qiwij62bmdugsd3gemhpy2)
+- [@trezy.codes](https://tangled.org/did:plc:4jrld6fwpnwqehtce56qshzv)
 - Could be your name here too!
 
 ### Tranquil PDS instances in the wild!

config.dev.toml

@@ -0,0 +1,30 @@
+[server]
+hostname = "pds.test"
+allow_http_proxy = true
+invite_code_required = false
+disable_rate_limiting = true
+
+[frontend]
+enabled = true
+dir = "/app/frontend/public"
+
+[database]
+url = "postgres://postgres:postgres@db:5432/pds"
+
+[storage]
+path = "/var/lib/tranquil-pds/blobs"
+
+[plc]
+directory_url = "http://plc:2582"
+
+[email]
+from_address = "noreply@pds.test"
+from_name = "Tranquil PDS (Dev)"
+
+[email.smarthost]
+host = "mailpit"
+port = 1025
+tls = "none"
+
+[secrets]
+allow_insecure = true

crates/tranquil-api/src/admin/signal.rs

@@ -9,7 +9,6 @@ use tranquil_pds::state::AppState;
 #[derive(Serialize)]
 #[serde(rename_all = "camelCase")]
 pub struct SignalStatusOutput {
-    pub enabled: bool,
     pub linked: bool,
 }
 
@@ -23,13 +22,12 @@ pub async fn get_signal_status(
     State(state): State<AppState>,
     _auth: Auth<Admin>,
 ) -> Result<Json<SignalStatusOutput>, ApiError> {
-    let enabled = tranquil_config::get().signal.enabled;
     let linked = match &state.signal_sender {
         Some(slot) => slot.is_linked().await,
         None => false,
     };
 
-    Ok(Json(SignalStatusOutput { enabled, linked }))
+    Ok(Json(SignalStatusOutput { linked }))
 }
 
 pub async fn link_signal_device(

crates/tranquil-api/src/identity/account.rs

@@ -510,6 +510,7 @@ pub async fn create_account(
         telegram_username: comms.telegram,
         signal_username: comms.signal,
         deactivated_at,
+        inbound_migration: is_migration || is_did_web_byod,
         encrypted_key_bytes: repo.encrypted_key_bytes,
         encryption_version: tranquil_pds::config::ENCRYPTION_VERSION,
         reserved_key_id,

crates/tranquil-api/src/repo/import.rs

@@ -106,7 +106,7 @@ pub async fn import_repo(
                 .map(|c| c.import.skip_verification)
                 .unwrap_or(false)
         });
-    let is_migration = user.deactivated_at.is_some();
+    let is_migration = user.inbound_migration && user.deactivated_at.is_some();
     if skip_verification {
         warn!("Skipping all CAR verification for import (SKIP_IMPORT_VERIFICATION=true)");
     } else if is_migration {

crates/tranquil-api/src/repo/record/batch.rs

@@ -27,7 +27,6 @@ struct WriteAccumulator {
     mst: Mst<TrackingBlockStore>,
     results: Vec<WriteResult>,
     ops: Vec<RecordOp>,
-    modified_keys: Vec<String>,
     all_blob_cids: Vec<String>,
     backlinks_to_add: Vec<Backlink>,
     backlinks_to_remove: Vec<AtUri>,
@@ -44,7 +43,6 @@ async fn process_single_write(
         mst,
         mut results,
         mut ops,
-        mut modified_keys,
         mut all_blob_cids,
         mut backlinks_to_add,
         mut backlinks_to_remove,
@@ -69,8 +67,19 @@ async fn process_single_write(
                     .await?,
                 )
             };
-            all_blob_cids.extend(extract_blob_cids(value));
             let rkey = rkey.clone().unwrap_or_else(Rkey::generate);
+            let key = format!("{}/{}", collection, rkey);
+            if mst
+                .get(&key)
+                .await
+                .map_err(|e| ApiError::InternalError(Some(format!("Failed to read MST: {e}"))))?
+                .is_some()
+            {
+                return Err(ApiError::InvalidRequest(format!(
+                    "Record already exists at {key}"
+                )));
+            }
+            all_blob_cids.extend(extract_blob_cids(value));
             let record_ipld = tranquil_pds::util::json_to_ipld(value);
             let record_bytes = serde_ipld_dagcbor::to_vec(&record_ipld)
                 .map_err(|_| ApiError::InvalidRecord("Failed to serialize record".into()))?;
@@ -78,8 +87,6 @@ async fn process_single_write(
                 .put(&record_bytes)
                 .await
                 .map_err(|_| ApiError::InternalError(Some("Failed to store record".into())))?;
-            let key = format!("{}/{}", collection, rkey);
-            modified_keys.push(key.clone());
             let new_mst = mst
                 .add(&key, record_cid)
                 .await
@@ -100,7 +107,6 @@ async fn process_single_write(
                 mst: new_mst,
                 results,
                 ops,
-                modified_keys,
                 all_blob_cids,
                 backlinks_to_add,
                 backlinks_to_remove,
@@ -124,16 +130,7 @@ async fn process_single_write(
                     .await?,
                 )
             };
-            all_blob_cids.extend(extract_blob_cids(value));
-            let record_ipld = tranquil_pds::util::json_to_ipld(value);
-            let record_bytes = serde_ipld_dagcbor::to_vec(&record_ipld)
-                .map_err(|_| ApiError::InvalidRecord("Failed to serialize record".into()))?;
-            let record_cid = tracking_store
-                .put(&record_bytes)
-                .await
-                .map_err(|_| ApiError::InternalError(Some("Failed to store record".into())))?;
             let key = format!("{}/{}", collection, rkey);
-            modified_keys.push(key.clone());
             let prev_record_cid = mst
                 .get(&key)
                 .await
@@ -143,6 +140,14 @@ async fn process_single_write(
                 .ok_or_else(|| {
                     ApiError::InvalidRequest("Update target record does not exist".into())
                 })?;
+            all_blob_cids.extend(extract_blob_cids(value));
+            let record_ipld = tranquil_pds::util::json_to_ipld(value);
+            let record_bytes = serde_ipld_dagcbor::to_vec(&record_ipld)
+                .map_err(|_| ApiError::InvalidRecord("Failed to serialize record".into()))?;
+            let record_cid = tracking_store
+                .put(&record_bytes)
+                .await
+                .map_err(|_| ApiError::InternalError(Some("Failed to store record".into())))?;
             let new_mst = mst
                 .update(&key, record_cid)
                 .await
@@ -165,7 +170,6 @@ async fn process_single_write(
                 mst: new_mst,
                 results,
                 ops,
-                modified_keys,
                 all_blob_cids,
                 backlinks_to_add,
                 backlinks_to_remove,
@@ -173,7 +177,6 @@ async fn process_single_write(
         }
         WriteOp::Delete { collection, rkey } => {
             let key = format!("{}/{}", collection, rkey);
-            modified_keys.push(key.clone());
             let prev_record_cid = mst
                 .get(&key)
                 .await
@@ -198,7 +201,6 @@ async fn process_single_write(
                 mst: new_mst,
                 results,
                 ops,
-                modified_keys,
                 all_blob_cids,
                 backlinks_to_add,
                 backlinks_to_remove,
@@ -219,7 +221,6 @@ async fn process_writes(
         mst: initial_mst,
         results: Vec::new(),
         ops: Vec::new(),
-        modified_keys: Vec::new(),
         all_blob_cids: Vec::new(),
         backlinks_to_add: Vec::new(),
         backlinks_to_remove: Vec::new(),
@@ -351,7 +352,6 @@ pub async fn apply_writes(
         mst: final_mst,
         results,
         ops,
-        modified_keys,
         all_blob_cids,
         backlinks_to_add,
         backlinks_to_remove,
@@ -407,7 +407,6 @@ pub async fn apply_writes(
             controller_did: controller_did.as_ref(),
             delegation_detail: write_summary,
             ops,
-            modified_keys: &modified_keys,
             blob_cids: &all_blob_cids,
             backlinks_to_add,
             backlinks_to_remove,

crates/tranquil-api/src/repo/record/delete.rs

@@ -74,7 +74,6 @@ pub async fn delete_record(
         prev: RecordCid::from(prev_record_cid),
     };
 
-    let modified_keys = [key];
     let deleted_uri = AtUri::from_parts(&did, &input.collection, &input.rkey);
 
     let commit_result = finalize_repo_write(
@@ -93,7 +92,6 @@ pub async fn delete_record(
                 })
             }),
             ops: vec![op],
-            modified_keys: &modified_keys,
             blob_cids: &[],
             backlinks_to_add: vec![],
             backlinks_to_remove: vec![deleted_uri],

crates/tranquil-api/src/repo/record/write.rs

@@ -179,6 +179,18 @@ pub async fn create_record(
         }
     }
 
+    let key = format!("{}/{}", input.collection, rkey);
+    if mst
+        .get(&key)
+        .await
+        .map_err(|e| ApiError::InternalError(Some(format!("Failed to read MST: {e}"))))?
+        .is_some()
+    {
+        return Err(ApiError::InvalidRequest(format!(
+            "Record already exists at {key}"
+        )));
+    }
+
     let record_ipld = tranquil_pds::util::json_to_ipld(&input.record);
     let record_bytes = serde_ipld_dagcbor::to_vec(&record_ipld)
         .map_err(|_| ApiError::InvalidRecord("Failed to serialize record".into()))?;
@@ -187,8 +199,6 @@ pub async fn create_record(
         .put(&record_bytes)
         .await
         .map_err(|_| ApiError::InternalError(Some("Failed to save record block".into())))?;
-
-    let key = format!("{}/{}", input.collection, rkey);
     mst = mst
         .add(&key, record_cid)
         .await
@@ -200,20 +210,6 @@ pub async fn create_record(
         cid: tranquil_pds::cid_types::RecordCid::from(record_cid),
     });
 
-    let modified_keys: Vec<String> = ops
-        .iter()
-        .map(|op| match op {
-            RecordOp::Create {
-                collection, rkey, ..
-            }
-            | RecordOp::Update {
-                collection, rkey, ..
-            }
-            | RecordOp::Delete {
-                collection, rkey, ..
-            } => format!("{}/{}", collection, rkey),
-        })
-        .collect();
     let blob_cids = extract_blob_cids(&input.record);
 
     let created_uri = AtUri::from_parts(&did, &input.collection, &rkey);
@@ -235,7 +231,6 @@ pub async fn create_record(
                 })
             }),
             ops,
-            modified_keys: &modified_keys,
             blob_cids: &blob_cids,
             backlinks_to_add,
             backlinks_to_remove: conflict_uris_to_cleanup,
@@ -367,7 +362,6 @@ pub async fn put_record(
         }
     };
 
-    let modified_keys = [key];
     let blob_cids = extract_blob_cids(&input.record);
     let backlinks_to_add = extract_backlinks(&record_uri, &input.record);
 
@@ -387,7 +381,6 @@ pub async fn put_record(
                 })
             }),
             ops: vec![op],
-            modified_keys: &modified_keys,
             blob_cids: &blob_cids,
             backlinks_to_add,
             backlinks_to_remove,

crates/tranquil-api/src/server/meta.rs

@@ -5,7 +5,7 @@ use tranquil_pds::BUILD_VERSION;
 use tranquil_pds::state::AppState;
 use tranquil_pds::util::{discord_app_id, discord_bot_username, telegram_bot_username};
 
-fn get_available_comms_channels() -> Vec<CommsChannel> {
+async fn get_available_comms_channels(state: &AppState) -> Vec<CommsChannel> {
     let cfg = tranquil_config::get();
     let mut channels = vec![CommsChannel::Email];
     if cfg.discord.bot_token.is_some() {
@@ -14,7 +14,9 @@ fn get_available_comms_channels() -> Vec<CommsChannel> {
     if cfg.telegram.bot_token.is_some() {
         channels.push(CommsChannel::Telegram);
     }
-    if cfg.signal.enabled {
+    if let Some(slot) = &state.signal_sender
+        && slot.is_linked().await
+    {
         channels.push(CommsChannel::Signal);
     }
     channels
@@ -66,7 +68,7 @@ pub struct DescribeServerOutput {
     pub telegram_bot_username: Option<String>,
 }
 
-pub async fn describe_server() -> Json<DescribeServerOutput> {
+pub async fn describe_server(State(state): State<AppState>) -> Json<DescribeServerOutput> {
     let cfg = tranquil_config::get();
     let pds_hostname = &cfg.server.hostname;
 
@@ -82,7 +84,7 @@ pub async fn describe_server() -> Json<DescribeServerOutput> {
             email: cfg.server.contact_email.clone(),
         },
         version: BUILD_VERSION,
-        available_comms_channels: get_available_comms_channels(),
+        available_comms_channels: get_available_comms_channels(&state).await,
         self_hosted_did_web_enabled: is_self_hosted_did_web_enabled(),
         discord_bot_username: discord_bot_username().map(String::from),
         discord_app_id: discord_app_id().map(String::from),

crates/tranquil-api/src/server/mod.rs

@@ -51,6 +51,7 @@ pub use session::{
     auto_resend_verification, confirm_signup, create_session, delete_session,
     get_legacy_login_preference, get_session, list_sessions, refresh_session, resend_verification,
     revoke_all_sessions, revoke_session, update_legacy_login_preference, update_locale,
+    verification_blocks_login,
 };
 pub use signing_key::reserve_signing_key;
 pub use totp::{

crates/tranquil-api/src/server/session.rs

@@ -8,7 +8,7 @@ use bcrypt::verify;
 use serde::{Deserialize, Serialize};
 use serde_json::json;
 use tracing::{error, info, warn};
-use tranquil_db_traits::{SessionId, TokenFamilyId};
+use tranquil_db_traits::{ChannelVerificationStatus, SessionId, TokenFamilyId};
 use tranquil_pds::api::error::{ApiError, DbResultExt};
 use tranquil_pds::api::{EmptyResponse, PreferredLocaleOutput, SuccessResponse};
 use tranquil_pds::auth::{
@@ -20,6 +20,13 @@ use tranquil_pds::state::AppState;
 use tranquil_pds::types::{AccountState, Did, Handle, PlainPassword};
 use tranquil_types::TokenId;
 
+pub fn verification_blocks_login(channel_verification: &ChannelVerificationStatus) -> bool {
+    !tranquil_config::get()
+        .server
+        .disable_account_verification_gate
+        && !channel_verification.has_any_verified()
+}
+
 #[derive(Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub struct CreateSessionInput {
@@ -129,14 +136,13 @@ pub async fn create_session(
         warn!("Login attempt for takendown account: {}", row.did);
         return Err(ApiError::AccountTakedown);
     }
-    let is_verified = row.channel_verification.has_any_verified();
     let is_delegated = state
         .repos
         .delegation
         .is_delegated_account(&row.did)
         .await
         .unwrap_or(false);
-    if !is_verified && !is_delegated {
+    if verification_blocks_login(&row.channel_verification) && !is_delegated {
         warn!("Login attempt for unverified account: {}", row.did);
         let resend_info = auto_resend_verification(&state, &row.did).await;
         let handle = resend_info

crates/tranquil-comms/Cargo.toml

@@ -10,7 +10,14 @@ tranquil-signal = { workspace = true }
 
 async-trait = { workspace = true }
 base64 = { workspace = true }
+ed25519-dalek = { workspace = true }
+futures = { workspace = true }
+hickory-resolver = { workspace = true }
+lettre = { workspace = true }
+rand = { workspace = true }
 reqwest = { workspace = true }
+rsa = { workspace = true }
+secrecy = { workspace = true }
 serde_json = { workspace = true }
 sqlx = { workspace = true }
 thiserror = { workspace = true }
@@ -18,3 +25,7 @@ tokio = { workspace = true }
 tracing = { workspace = true }
 tranquil-db-traits = { workspace = true }
 uuid = { workspace = true }
+
+[dev-dependencies]
+chrono = { workspace = true }
+tokio = { workspace = true, features = ["macros", "rt-multi-thread", "time", "io-util", "net"] }

crates/tranquil-comms/src/email/dkim.rs

@@ -0,0 +1,227 @@
+use std::fs;
+
+use base64::Engine;
+use base64::engine::general_purpose::STANDARD as BASE64_STANDARD;
+use ed25519_dalek::pkcs8::DecodePrivateKey as _;
+use lettre::Message;
+use lettre::message::dkim::{
+    DkimCanonicalization, DkimCanonicalizationType, DkimConfig as LettreDkimConfig,
+    DkimSigningAlgorithm, DkimSigningKey,
+};
+use lettre::message::header::HeaderName;
+use rsa::pkcs1::EncodeRsaPrivateKey;
+use rsa::pkcs8::LineEnding;
+
+use super::types::{DkimKeyPath, DkimSelector, EmailDomain};
+use crate::sender::SendError;
+
+const SIGNED_HEADERS: &[&str] = &[
+    "From",
+    "Sender",
+    "Reply-To",
+    "To",
+    "Cc",
+    "Subject",
+    "Date",
+    "In-Reply-To",
+    "References",
+    "MIME-Version",
+    "Content-Type",
+    "Content-Transfer-Encoding",
+];
+
+pub struct DkimSigner {
+    config: LettreDkimConfig,
+}
+
+impl DkimSigner {
+    pub fn load(
+        selector: DkimSelector,
+        domain: EmailDomain,
+        path: DkimKeyPath,
+    ) -> Result<Self, SendError> {
+        let pem = fs::read_to_string(path.as_path()).map_err(|e| {
+            SendError::DkimSign(format!("read DKIM key {}: {e}", path.as_path().display()))
+        })?;
+        Self::from_pem(selector, domain, &pem)
+    }
+
+    pub fn from_pem(
+        selector: DkimSelector,
+        domain: EmailDomain,
+        pem: &str,
+    ) -> Result<Self, SendError> {
+        let key = parse_key(pem)?;
+        let canonicalization = DkimCanonicalization {
+            header: DkimCanonicalizationType::Relaxed,
+            body: DkimCanonicalizationType::Relaxed,
+        };
+        let headers = SIGNED_HEADERS
+            .iter()
+            .copied()
+            .map(HeaderName::new_from_ascii_str)
+            .collect();
+        let config = LettreDkimConfig::new(
+            selector.into_inner(),
+            domain.into_inner(),
+            key,
+            headers,
+            canonicalization,
+        );
+        Ok(Self { config })
+    }
+
+    pub fn sign(&self, message: &mut Message) {
+        message.sign(&self.config);
+    }
+}
+
+impl std::fmt::Debug for DkimSigner {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str("DkimSigner")
+    }
+}
+
+fn parse_key(input: &str) -> Result<DkimSigningKey, SendError> {
+    let trimmed = input.trim_start();
+    match trimmed {
+        s if s.starts_with("-----BEGIN RSA PRIVATE KEY-----") => {
+            DkimSigningKey::new(input, DkimSigningAlgorithm::Rsa)
+                .map_err(|e| SendError::DkimSign(format!("RSA PKCS#1 PEM rejected: {e}")))
+        }
+        s if s.starts_with("-----BEGIN PRIVATE KEY-----") => parse_pkcs8(input),
+        s if s.starts_with("-----BEGIN") => Err(SendError::DkimSign(
+            "unrecognized PEM type; expected an RSA or Ed25519 private key".to_string(),
+        )),
+        _ => DkimSigningKey::new(input.trim(), DkimSigningAlgorithm::Ed25519).map_err(|e| {
+            SendError::DkimSign(format!(
+                "expected base64-encoded 32-byte Ed25519 seed or a PEM-wrapped key: {e}"
+            ))
+        }),
+    }
+}
+
+fn parse_pkcs8(pem: &str) -> Result<DkimSigningKey, SendError> {
+    let ed25519_err = match ed25519_dalek::SigningKey::from_pkcs8_pem(pem) {
+        Ok(key) => {
+            let seed = BASE64_STANDARD.encode(key.to_bytes());
+            return DkimSigningKey::new(&seed, DkimSigningAlgorithm::Ed25519)
+                .map_err(|e| SendError::DkimSign(format!("re-import Ed25519 seed: {e}")));
+        }
+        Err(e) => e,
+    };
+
+    let rsa_err = match rsa::RsaPrivateKey::from_pkcs8_pem(pem) {
+        Ok(key) => {
+            let pkcs1 = key
+                .to_pkcs1_pem(LineEnding::LF)
+                .map_err(|e| SendError::DkimSign(format!("re-encode RSA PKCS#8 as PKCS#1: {e}")))?;
+            return DkimSigningKey::new(pkcs1.as_str(), DkimSigningAlgorithm::Rsa)
+                .map_err(|e| SendError::DkimSign(format!("re-import RSA PKCS#1: {e}")));
+        }
+        Err(e) => e,
+    };
+
+    Err(SendError::DkimSign(format!(
+        "PKCS#8 PEM rejected by both parsers; ed25519: {ed25519_err}; rsa: {rsa_err}"
+    )))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use ed25519_dalek::pkcs8::EncodePrivateKey as _;
+    use lettre::message::Mailbox;
+    use lettre::message::header::ContentType;
+    use rsa::pkcs1::DecodeRsaPrivateKey as _;
+
+    const ED25519_RAW_SEED_B64: &str = "QkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkI=";
+
+    const RSA_PKCS1_PEM: &str = include_str!("test_fixtures/rsa2048-priv-pkcs1.pem");
+
+    fn ed25519_pkcs8_pem() -> String {
+        let key = ed25519_dalek::SigningKey::from_bytes(&[7u8; 32]);
+        key.to_pkcs8_pem(LineEnding::LF).unwrap().to_string()
+    }
+
+    fn rsa_pkcs8_pem() -> String {
+        let key = rsa::RsaPrivateKey::from_pkcs1_pem(RSA_PKCS1_PEM).unwrap();
+        key.to_pkcs8_pem(LineEnding::LF).unwrap().to_string()
+    }
+
+    fn signer(pem: &str) -> DkimSigner {
+        DkimSigner::from_pem(
+            DkimSelector::parse("default").unwrap(),
+            EmailDomain::parse("nel.pet").unwrap(),
+            pem,
+        )
+        .expect("key should load")
+    }
+
+    fn signed_headers(signer: &DkimSigner) -> String {
+        let from: Mailbox = "sender@nel.pet".parse().unwrap();
+        let to: Mailbox = "recipient@nel.pet".parse().unwrap();
+        let mut message = Message::builder()
+            .from(from)
+            .to(to)
+            .subject("Roundtrip")
+            .header(ContentType::TEXT_PLAIN)
+            .body("Body".to_string())
+            .unwrap();
+        signer.sign(&mut message);
+        String::from_utf8(message.formatted()).unwrap()
+    }
+
+    #[test]
+    fn rejects_garbage() {
+        assert!(matches!(
+            parse_key("not a key"),
+            Err(SendError::DkimSign(_))
+        ));
+    }
+
+    #[test]
+    fn rejects_unknown_pem_type() {
+        let pem = "-----BEGIN OPENSSH PRIVATE KEY-----\nx\n-----END OPENSSH PRIVATE KEY-----\n";
+        match parse_key(pem) {
+            Err(SendError::DkimSign(msg)) => assert!(msg.contains("unrecognized"), "msg: {msg}"),
+            other => panic!("expected unrecognized PEM error, got {other:?}"),
+        }
+    }
+
+    #[test]
+    fn ed25519_raw_seed_signs() {
+        let raw = signed_headers(&signer(ED25519_RAW_SEED_B64));
+        assert_signed_with(&raw, "a=ed25519-sha256");
+    }
+
+    #[test]
+    fn ed25519_pkcs8_pem_signs() {
+        let raw = signed_headers(&signer(&ed25519_pkcs8_pem()));
+        assert_signed_with(&raw, "a=ed25519-sha256");
+    }
+
+    #[test]
+    fn rsa_pkcs1_pem_signs() {
+        let raw = signed_headers(&signer(RSA_PKCS1_PEM));
+        assert_signed_with(&raw, "a=rsa-sha256");
+    }
+
+    #[test]
+    fn rsa_pkcs8_pem_signs() {
+        let raw = signed_headers(&signer(&rsa_pkcs8_pem()));
+        assert_signed_with(&raw, "a=rsa-sha256");
+    }
+
+    fn assert_signed_with(raw: &str, algorithm: &str) {
+        assert!(
+            raw.contains("DKIM-Signature:"),
+            "no signature header: {raw}"
+        );
+        assert!(raw.contains(algorithm), "missing {algorithm}: {raw}");
+        assert!(
+            raw.contains("c=relaxed/relaxed"),
+            "expected relaxed/relaxed canonicalization: {raw}"
+        );
+    }
+}

crates/tranquil-comms/src/email/message.rs

@@ -0,0 +1,151 @@
+use lettre::Message;
+use lettre::message::Mailbox;
+use lettre::message::header::ContentType;
+use uuid::Uuid;
+
+use super::types::EmailDomain;
+use crate::sender::SendError;
+use crate::types::QueuedComms;
+
+pub(super) fn build(from: &Mailbox, qc: &QueuedComms) -> Result<Message, SendError> {
+    let to: Mailbox = qc
+        .recipient
+        .parse()
+        .map_err(|e: lettre::address::AddressError| SendError::InvalidRecipient(e.to_string()))?;
+    let subject = qc.subject.as_deref().unwrap_or("Notification");
+    let message_id = format!("<{}@{}>", Uuid::new_v4(), from.email.domain());
+    Message::builder()
+        .from(from.clone())
+        .to(to)
+        .subject(subject)
+        .message_id(Some(message_id))
+        .header(ContentType::TEXT_PLAIN)
+        .body(qc.body.clone())
+        .map_err(|e| SendError::MessageBuild(e.to_string()))
+}
+
+pub(super) fn recipient_domain(message: &Message) -> Result<EmailDomain, SendError> {
+    let envelope = message.envelope();
+    let first = envelope
+        .to()
+        .first()
+        .ok_or_else(|| SendError::MessageBuild("envelope has no recipients".to_string()))?;
+    EmailDomain::parse(first.domain())
+        .map_err(|e| SendError::InvalidRecipient(format!("invalid recipient domain: {e}")))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::types::{CommsChannel, CommsStatus, CommsType};
+    use chrono::Utc;
+    use uuid::Uuid;
+
+    fn from_mailbox() -> Mailbox {
+        "Test Sender <noreply@nel.pet>".parse().unwrap()
+    }
+
+    fn fixture(recipient: &str, subject: Option<&str>, body: &str) -> QueuedComms {
+        QueuedComms {
+            id: Uuid::new_v4(),
+            user_id: None,
+            channel: CommsChannel::Email,
+            comms_type: CommsType::Welcome,
+            status: CommsStatus::Pending,
+            recipient: recipient.to_string(),
+            subject: subject.map(String::from),
+            body: body.to_string(),
+            metadata: None,
+            attempts: 0,
+            max_attempts: 3,
+            last_error: None,
+            created_at: Utc::now(),
+            updated_at: Utc::now(),
+            scheduled_for: Utc::now(),
+            processed_at: None,
+        }
+    }
+
+    #[test]
+    fn build_basic_message() {
+        let msg = build(
+            &from_mailbox(),
+            &fixture("user@nel.pet", Some("Welcome"), "Hello world."),
+        )
+        .unwrap();
+        let raw = String::from_utf8(msg.formatted()).unwrap();
+        let lower = raw.to_lowercase();
+        assert!(raw.contains("From: \"Test Sender\" <noreply@nel.pet>"));
+        assert!(raw.contains("To: user@nel.pet"));
+        assert!(raw.contains("Subject: Welcome"));
+        assert!(lower.contains("content-type: text/plain"));
+        assert!(raw.contains("Hello world."));
+    }
+
+    #[test]
+    fn utf8_subject_is_encoded() {
+        let msg = build(
+            &from_mailbox(),
+            &fixture("user@nel.pet", Some("héllo wörld"), "Body"),
+        )
+        .unwrap();
+        let raw = String::from_utf8(msg.formatted()).unwrap();
+        assert!(raw.contains("=?utf-8?"));
+        assert!(!raw.contains("héllo"));
+    }
+
+    #[test]
+    fn header_injection_rejected() {
+        let result = build(
+            &from_mailbox(),
+            &fixture("x@nel.pet\r\nBcc: evil@x", Some("s"), "b"),
+        );
+        assert!(matches!(result, Err(SendError::InvalidRecipient(_))));
+    }
+
+    #[test]
+    fn subject_crlf_does_not_inject_headers() {
+        let msg = build(
+            &from_mailbox(),
+            &fixture("user@nel.pet", Some("hi\r\nBcc: evil@nel.pet"), "body"),
+        )
+        .expect("subject CRLF should be encoded, not rejected");
+        let raw = String::from_utf8(msg.formatted()).unwrap();
+        assert!(
+            !raw.contains("Bcc:"),
+            "CRLF in subject must not produce a Bcc header: {raw}"
+        );
+        assert!(
+            raw.contains("Subject: ="),
+            "subject with non-printable chars should be RFC 2047 encoded: {raw}"
+        );
+    }
+
+    #[test]
+    fn message_id_uses_from_domain() {
+        let msg = build(&from_mailbox(), &fixture("user@nel.pet", Some("s"), "b")).unwrap();
+        let raw = String::from_utf8(msg.formatted()).unwrap();
+        let line = raw
+            .lines()
+            .find(|l| l.starts_with("Message-ID:") || l.starts_with("Message-Id:"))
+            .expect("message-id header present");
+        assert!(
+            line.contains("@nel.pet>"),
+            "message-id should use From domain: {line}"
+        );
+    }
+
+    #[test]
+    fn missing_subject_uses_default() {
+        let msg = build(&from_mailbox(), &fixture("user@nel.pet", None, "Body")).unwrap();
+        let raw = String::from_utf8(msg.formatted()).unwrap();
+        assert!(raw.contains("Subject: Notification"));
+    }
+
+    #[test]
+    fn recipient_domain_extracted() {
+        let msg = build(&from_mailbox(), &fixture("user@Nel.PET", Some("s"), "b")).unwrap();
+        let d = recipient_domain(&msg).unwrap();
+        assert_eq!(d.as_str(), "nel.pet");
+    }
+}

crates/tranquil-comms/src/email/mod.rs

@@ -0,0 +1,194 @@
+pub mod dkim;
+pub mod message;
+mod mx;
+pub mod transport;
+pub mod types;
+
+use std::sync::Arc;
+use std::time::Duration;
+
+use async_trait::async_trait;
+use hickory_resolver::TokioAsyncResolver;
+use lettre::message::Mailbox;
+use lettre::transport::smtp::AsyncSmtpTransport;
+use lettre::transport::smtp::PoolConfig;
+use lettre::transport::smtp::authentication::Credentials;
+use lettre::transport::smtp::extension::ClientId;
+use tokio::sync::Semaphore;
+use tracing::{info, warn};
+
+pub use self::dkim::DkimSigner;
+pub use self::transport::SendMode;
+use self::types::{
+    DkimKeyPath, DkimSelector, EmailDomain, HeloName, SmtpHost, SmtpPassword, SmtpPort,
+    SmtpUsername, TlsMode,
+};
+use crate::sender::{CommsSender, SendError};
+use crate::types::{CommsChannel, QueuedComms};
+
+pub struct EmailSender {
+    from: Mailbox,
+    mode: SendMode,
+    dkim: Option<DkimSigner>,
+}
+
+impl EmailSender {
+    pub fn new(from: Mailbox, mode: SendMode, dkim: Option<DkimSigner>) -> Self {
+        Self { from, mode, dkim }
+    }
+
+    pub fn from_config(cfg: &tranquil_config::TranquilConfig) -> Result<Option<Self>, SendError> {
+        let Some(from_address) = cfg.email.from_address.as_deref().filter(|s| !s.is_empty()) else {
+            info!("Email sender disabled: MAIL_FROM_ADDRESS unset");
+            return Ok(None);
+        };
+        let from = build_from(&cfg.email.from_name, from_address)?;
+        let dkim = build_dkim(&cfg.email.dkim)?;
+        let mode = match cfg
+            .email
+            .smarthost
+            .host
+            .as_deref()
+            .filter(|h| !h.is_empty())
+        {
+            Some(host) => build_smarthost(cfg, host)?,
+            None => build_direct_mx(cfg)?,
+        };
+        info!(?mode, dkim = dkim.is_some(), "Email sender initialized");
+        Ok(Some(Self { from, mode, dkim }))
+    }
+}
+
+fn config_invalid(field: &str, error: impl std::fmt::Display) -> SendError {
+    SendError::ConfigInvalid(format!("{field}: {error}"))
+}
+
+fn build_from(from_name: &str, from_address: &str) -> Result<Mailbox, SendError> {
+    let raw = match from_name.is_empty() {
+        true => from_address.to_string(),
+        false => format!("\"{}\" <{}>", from_name.replace('"', "'"), from_address),
+    };
+    raw.parse::<Mailbox>()
+        .map_err(|e| config_invalid("MAIL_FROM_ADDRESS / MAIL_FROM_NAME", e))
+}
+
+fn build_smarthost(
+    cfg: &tranquil_config::TranquilConfig,
+    host_raw: &str,
+) -> Result<SendMode, SendError> {
+    let host = SmtpHost::parse(host_raw).map_err(|e| config_invalid("MAIL_SMARTHOST_HOST", e))?;
+    let port = SmtpPort::parse(cfg.email.smarthost.port)
+        .map_err(|e| config_invalid("MAIL_SMARTHOST_PORT", e))?;
+    let tls = TlsMode::parse(&cfg.email.smarthost.tls)
+        .map_err(|e| config_invalid("MAIL_SMARTHOST_TLS", e))?;
+    let helo = resolve_helo(cfg)?;
+    let pool = PoolConfig::new()
+        .max_size(cfg.email.smarthost.pool_size)
+        .idle_timeout(Duration::from_secs(60));
+    let command_timeout = Duration::from_secs(cfg.email.smarthost.command_timeout_secs);
+    let total_timeout = Duration::from_secs(cfg.email.smarthost.total_timeout_secs);
+
+    let builder = match tls {
+        TlsMode::Implicit => AsyncSmtpTransport::<lettre::Tokio1Executor>::relay(host.as_str())
+            .map_err(|e| config_invalid("smarthost TLS setup", e))?,
+        TlsMode::Starttls => {
+            AsyncSmtpTransport::<lettre::Tokio1Executor>::starttls_relay(host.as_str())
+                .map_err(|e| config_invalid("smarthost TLS setup", e))?
+        }
+        TlsMode::None => {
+            AsyncSmtpTransport::<lettre::Tokio1Executor>::builder_dangerous(host.as_str())
+        }
+    };
+    let builder = builder
+        .port(port.as_u16())
+        .hello_name(ClientId::Domain(helo.into_inner()))
+        .timeout(Some(command_timeout))
+        .pool_config(pool);
+    let builder = match (
+        cfg.email.smarthost.username.as_deref(),
+        cfg.email.smarthost.password.as_deref(),
+    ) {
+        (Some(u), Some(p)) => {
+            let username =
+                SmtpUsername::parse(u).map_err(|e| config_invalid("MAIL_SMARTHOST_USERNAME", e))?;
+            let password =
+                SmtpPassword::parse(p).map_err(|e| config_invalid("MAIL_SMARTHOST_PASSWORD", e))?;
+            builder.credentials(Credentials::new(
+                username.into_inner(),
+                password.expose().to_string(),
+            ))
+        }
+        _ => builder,
+    };
+    Ok(SendMode::Smarthost {
+        transport: Box::new(builder.build()),
+        total_timeout,
+    })
+}
+
+fn build_direct_mx(cfg: &tranquil_config::TranquilConfig) -> Result<SendMode, SendError> {
+    let helo = resolve_helo(cfg)?;
+    let resolver = TokioAsyncResolver::tokio_from_system_conf()
+        .map(Arc::new)
+        .map_err(|e| config_invalid("system DNS configuration", e))?;
+    let max_concurrent = cfg.email.direct_mx.max_concurrent_sends.max(1);
+    Ok(SendMode::DirectMx {
+        resolver,
+        helo,
+        command_timeout: Duration::from_secs(cfg.email.direct_mx.command_timeout_secs),
+        total_timeout: Duration::from_secs(cfg.email.direct_mx.total_timeout_secs),
+        require_tls: cfg.email.direct_mx.require_tls,
+        inflight: Arc::new(Semaphore::new(max_concurrent)),
+    })
+}
+
+fn resolve_helo(cfg: &tranquil_config::TranquilConfig) -> Result<HeloName, SendError> {
+    let raw = cfg
+        .email
+        .helo_name
+        .clone()
+        .unwrap_or_else(|| cfg.server.hostname_without_port().to_string());
+    HeloName::parse(&raw).map_err(|e| config_invalid(&format!("HELO name {raw:?}"), e))
+}
+
+fn build_dkim(cfg: &tranquil_config::DkimConfig) -> Result<Option<DkimSigner>, SendError> {
+    let selector = match cfg.selector.as_deref() {
+        Some(s) => s,
+        None => return Ok(None),
+    };
+    let domain = cfg
+        .domain
+        .as_deref()
+        .ok_or_else(|| SendError::DkimSign("MAIL_DKIM_DOMAIN required when selector set".into()))?;
+    let key_path = cfg.private_key_path.as_deref().ok_or_else(|| {
+        SendError::DkimSign("MAIL_DKIM_KEY_PATH required when selector set".into())
+    })?;
+    let selector = DkimSelector::parse(selector)
+        .map_err(|e| SendError::DkimSign(format!("invalid DKIM selector: {e}")))?;
+    let domain = EmailDomain::parse(domain)
+        .map_err(|e| SendError::DkimSign(format!("invalid DKIM domain: {e}")))?;
+    let path = DkimKeyPath::parse(key_path)
+        .map_err(|e| SendError::DkimSign(format!("DKIM key path invalid: {e}")))?;
+    DkimSigner::load(selector, domain, path).map(Some)
+}
+
+#[async_trait]
+impl CommsSender for EmailSender {
+    fn channel(&self) -> CommsChannel {
+        CommsChannel::Email
+    }
+
+    async fn send(&self, notification: &QueuedComms) -> Result<(), SendError> {
+        let mut message = message::build(&self.from, notification)?;
+        if let Some(signer) = &self.dkim {
+            signer.sign(&mut message);
+        }
+        match transport::dispatch(&self.mode, message).await {
+            Ok(()) => Ok(()),
+            Err(e) => {
+                warn!(comms_id = %notification.id, error = %e, "SMTP send failed");
+                Err(e)
+            }
+        }
+    }
+}

crates/tranquil-comms/src/email/mx.rs

@@ -0,0 +1,250 @@
+use hickory_resolver::TokioAsyncResolver;
+use hickory_resolver::error::{ResolveError, ResolveErrorKind};
+use hickory_resolver::proto::op::ResponseCode;
+use rand::seq::SliceRandom;
+
+use super::types::{EmailDomain, MxHost, MxPriority, MxRecord};
+use crate::sender::SendError;
+
+pub async fn resolve(
+    resolver: &TokioAsyncResolver,
+    domain: &EmailDomain,
+) -> Result<Vec<MxRecord>, SendError> {
+    match resolver.mx_lookup(domain.as_str()).await {
+        Ok(lookup) => interpret_lookup(
+            lookup
+                .iter()
+                .map(|mx| (mx.preference(), mx.exchange().clone())),
+            domain,
+        ),
+        Err(e) => classify_lookup_error(e, domain),
+    }
+}
+
+fn interpret_lookup(
+    items: impl IntoIterator<Item = (u16, hickory_resolver::Name)>,
+    domain: &EmailDomain,
+) -> Result<Vec<MxRecord>, SendError> {
+    let entries: Vec<_> = items.into_iter().collect();
+    match entries.iter().any(|(_, name)| name.is_root()) {
+        true => Err(SendError::DnsPermanent(format!(
+            "null MX record at {}: domain refuses mail",
+            domain.as_str()
+        ))),
+        false => {
+            let records: Vec<MxRecord> = entries
+                .into_iter()
+                .filter_map(|(prio, name)| {
+                    MxHost::parse(&name.to_utf8()).ok().map(|host| MxRecord {
+                        priority: MxPriority::new(prio),
+                        host,
+                    })
+                })
+                .collect();
+            match records.is_empty() {
+                true => implicit_mx(domain),
+                false => Ok(prioritize(records)),
+            }
+        }
+    }
+}
+
+fn prioritize(mut records: Vec<MxRecord>) -> Vec<MxRecord> {
+    records.shuffle(&mut rand::thread_rng());
+    records.sort_by_key(|r| r.priority);
+    records
+}
+
+fn classify_lookup_error(
+    e: ResolveError,
+    domain: &EmailDomain,
+) -> Result<Vec<MxRecord>, SendError> {
+    match e.kind() {
+        ResolveErrorKind::NoRecordsFound { response_code, .. } => match *response_code {
+            ResponseCode::NoError => implicit_mx(domain),
+            ResponseCode::NXDomain => Err(SendError::DnsPermanent(format!(
+                "domain {} does not exist",
+                domain.as_str()
+            ))),
+            other => Err(SendError::DnsTransient(format!(
+                "MX lookup for {} failed with {other}",
+                domain.as_str()
+            ))),
+        },
+        _ => Err(SendError::DnsTransient(e.to_string())),
+    }
+}
+
+fn implicit_mx(domain: &EmailDomain) -> Result<Vec<MxRecord>, SendError> {
+    MxHost::parse(domain.as_str())
+        .map(|host| {
+            vec![MxRecord {
+                priority: MxPriority::new(0),
+                host,
+            }]
+        })
+        .map_err(|e| SendError::DnsPermanent(format!("invalid recipient domain: {e}")))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn record(prio: u16, host: &str) -> MxRecord {
+        MxRecord {
+            priority: MxPriority::new(prio),
+            host: MxHost::parse(host).unwrap(),
+        }
+    }
+
+    #[test]
+    fn prioritize_sorts_by_priority_ascending() {
+        let result = prioritize(vec![
+            record(20, "mx2.nel.pet"),
+            record(10, "mx1.nel.pet"),
+            record(10, "mx1b.nel.pet"),
+        ]);
+        assert_eq!(result[0].priority.as_u16(), 10);
+        assert_eq!(result[1].priority.as_u16(), 10);
+        assert_eq!(result[2].priority.as_u16(), 20);
+    }
+
+    #[test]
+    fn prioritize_randomizes_equal_priority_order() {
+        let attempts: Vec<Vec<String>> = (0..200)
+            .map(|_| {
+                prioritize(vec![
+                    record(10, "a.nel.pet"),
+                    record(10, "b.nel.pet"),
+                    record(10, "c.nel.pet"),
+                    record(10, "d.nel.pet"),
+                ])
+                .into_iter()
+                .map(|r| r.host.as_str().to_string())
+                .collect()
+            })
+            .collect();
+        let distinct: std::collections::HashSet<_> = attempts.iter().cloned().collect();
+        assert!(
+            distinct.len() > 1,
+            "equal-priority MX order should vary across calls; got only {}",
+            distinct.len()
+        );
+    }
+
+    #[test]
+    fn implicit_mx_uses_domain_as_host() {
+        let d = EmailDomain::parse("nel.pet").unwrap();
+        let result = implicit_mx(&d).unwrap();
+        assert_eq!(result.len(), 1);
+        assert_eq!(result[0].priority.as_u16(), 0);
+        assert_eq!(result[0].host.as_str(), "nel.pet");
+    }
+
+    #[test]
+    fn no_error_response_yields_implicit_mx() {
+        let d = EmailDomain::parse("nel.pet").unwrap();
+        let err = ResolveError::from(ResolveErrorKind::NoRecordsFound {
+            query: Box::new(hickory_resolver::proto::op::Query::default()),
+            soa: None,
+            negative_ttl: None,
+            response_code: ResponseCode::NoError,
+            trusted: false,
+        });
+        let result = classify_lookup_error(err, &d).unwrap();
+        assert_eq!(result.len(), 1);
+        assert_eq!(result[0].host.as_str(), "nel.pet");
+    }
+
+    #[test]
+    fn nxdomain_response_is_permanent() {
+        let d = EmailDomain::parse("does-not-exist.invalid").unwrap();
+        let err = ResolveError::from(ResolveErrorKind::NoRecordsFound {
+            query: Box::new(hickory_resolver::proto::op::Query::default()),
+            soa: None,
+            negative_ttl: None,
+            response_code: ResponseCode::NXDomain,
+            trusted: true,
+        });
+        match classify_lookup_error(err, &d) {
+            Err(SendError::DnsPermanent(_)) => {}
+            other => panic!("expected DnsPermanent, got {other:?}"),
+        }
+    }
+
+    #[test]
+    fn servfail_response_is_transient() {
+        let d = EmailDomain::parse("nel.pet").unwrap();
+        let err = ResolveError::from(ResolveErrorKind::NoRecordsFound {
+            query: Box::new(hickory_resolver::proto::op::Query::default()),
+            soa: None,
+            negative_ttl: None,
+            response_code: ResponseCode::ServFail,
+            trusted: false,
+        });
+        match classify_lookup_error(err, &d) {
+            Err(SendError::DnsTransient(_)) => {}
+            other => panic!("expected DnsTransient, got {other:?}"),
+        }
+    }
+
+    #[test]
+    fn timeout_is_transient() {
+        let d = EmailDomain::parse("nel.pet").unwrap();
+        let err = ResolveError::from(ResolveErrorKind::Timeout);
+        match classify_lookup_error(err, &d) {
+            Err(SendError::DnsTransient(_)) => {}
+            other => panic!("expected DnsTransient, got {other:?}"),
+        }
+    }
+
+    #[test]
+    fn message_variant_is_transient() {
+        let d = EmailDomain::parse("nel.pet").unwrap();
+        let err = ResolveError::from(ResolveErrorKind::Message("transient resolver glitch"));
+        match classify_lookup_error(err, &d) {
+            Err(SendError::DnsTransient(_)) => {}
+            other => panic!("expected DnsTransient default, got {other:?}"),
+        }
+    }
+
+    #[test]
+    fn null_mx_is_permanent() {
+        let d = EmailDomain::parse("nomail.nel.pet").unwrap();
+        let result = interpret_lookup(vec![(0, hickory_resolver::Name::root())], &d);
+        match result {
+            Err(SendError::DnsPermanent(msg)) => {
+                assert!(msg.contains("null MX"), "msg: {msg}")
+            }
+            other => panic!("expected DnsPermanent, got {other:?}"),
+        }
+    }
+
+    #[test]
+    fn null_mx_alongside_real_records_still_permanent() {
+        let d = EmailDomain::parse("mixed.nel.pet").unwrap();
+        let real = hickory_resolver::Name::from_ascii("mx1.nel.pet.").unwrap();
+        let result = interpret_lookup(vec![(10, real), (0, hickory_resolver::Name::root())], &d);
+        assert!(matches!(result, Err(SendError::DnsPermanent(_))));
+    }
+
+    #[test]
+    fn empty_lookup_uses_implicit_mx() {
+        let d = EmailDomain::parse("nel.pet").unwrap();
+        let result = interpret_lookup(Vec::<(u16, hickory_resolver::Name)>::new(), &d).unwrap();
+        assert_eq!(result.len(), 1);
+        assert_eq!(result[0].host.as_str(), "nel.pet");
+    }
+
+    #[test]
+    fn valid_records_pass_through_with_priority_sort() {
+        let d = EmailDomain::parse("nel.pet").unwrap();
+        let mx1 = hickory_resolver::Name::from_ascii("mx1.nel.pet.").unwrap();
+        let mx2 = hickory_resolver::Name::from_ascii("mx2.nel.pet.").unwrap();
+        let result = interpret_lookup(vec![(20, mx2), (10, mx1)], &d).unwrap();
+        assert_eq!(result.len(), 2);
+        assert_eq!(result[0].priority.as_u16(), 10);
+        assert_eq!(result[0].host.as_str(), "mx1.nel.pet");
+        assert_eq!(result[1].priority.as_u16(), 20);
+    }
+}

crates/tranquil-comms/src/email/test_fixtures/rsa2048-priv-pkcs1.pem

@@ -0,0 +1,27 @@
+-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----

crates/tranquil-comms/src/email/transport.rs

@@ -0,0 +1,164 @@
+use std::sync::Arc;
+use std::time::Duration;
+
+use futures::StreamExt;
+use hickory_resolver::TokioAsyncResolver;
+use lettre::transport::smtp::AsyncSmtpTransport;
+use lettre::transport::smtp::Error as SmtpError;
+use lettre::transport::smtp::client::{Tls, TlsParameters};
+use lettre::transport::smtp::extension::ClientId;
+use lettre::{AsyncTransport, Message, Tokio1Executor};
+use tokio::sync::Semaphore;
+
+use super::message::recipient_domain;
+use super::mx;
+use super::types::{HeloName, MxRecord};
+use crate::sender::SendError;
+
+pub enum SendMode {
+    Smarthost {
+        transport: Box<AsyncSmtpTransport<Tokio1Executor>>,
+        total_timeout: Duration,
+    },
+    DirectMx {
+        resolver: Arc<TokioAsyncResolver>,
+        helo: HeloName,
+        command_timeout: Duration,
+        total_timeout: Duration,
+        require_tls: bool,
+        inflight: Arc<Semaphore>,
+    },
+}
+
+impl std::fmt::Debug for SendMode {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::Smarthost { total_timeout, .. } => {
+                write!(f, "SendMode::Smarthost(total_timeout={total_timeout:?})")
+            }
+            Self::DirectMx {
+                helo, require_tls, ..
+            } => write!(
+                f,
+                "SendMode::DirectMx({}, require_tls={require_tls})",
+                helo.as_str()
+            ),
+        }
+    }
+}
+
+pub async fn dispatch(mode: &SendMode, message: Message) -> Result<(), SendError> {
+    match mode {
+        SendMode::Smarthost {
+            transport,
+            total_timeout,
+        } => with_total_timeout(*total_timeout, run_send(transport, message)).await,
+        SendMode::DirectMx {
+            resolver,
+            helo,
+            command_timeout,
+            total_timeout,
+            require_tls,
+            inflight,
+        } => {
+            with_total_timeout(*total_timeout, async {
+                let _permit =
+                    inflight.clone().acquire_owned().await.map_err(|_| {
+                        SendError::SmtpTransient("send semaphore closed".to_string())
+                    })?;
+                send_direct(
+                    resolver.as_ref(),
+                    helo,
+                    *command_timeout,
+                    *require_tls,
+                    message,
+                )
+                .await
+            })
+            .await
+        }
+    }
+}
+
+async fn with_total_timeout<F: std::future::Future<Output = Result<(), SendError>>>(
+    total: Duration,
+    fut: F,
+) -> Result<(), SendError> {
+    tokio::time::timeout(total, fut)
+        .await
+        .unwrap_or(Err(SendError::Timeout))
+}
+
+async fn run_send(
+    transport: &AsyncSmtpTransport<Tokio1Executor>,
+    message: Message,
+) -> Result<(), SendError> {
+    transport
+        .send(message)
+        .await
+        .map(|_| ())
+        .map_err(classify_smtp_error)
+}
+
+async fn send_direct(
+    resolver: &TokioAsyncResolver,
+    helo: &HeloName,
+    command_timeout: Duration,
+    require_tls: bool,
+    message: Message,
+) -> Result<(), SendError> {
+    let domain = recipient_domain(&message)?;
+    let mxs = mx::resolve(resolver, &domain).await?;
+    let outcome = futures::stream::iter(mxs)
+        .fold(None::<Result<(), SendError>>, |acc, mx_record| {
+            let message = message.clone();
+            async move {
+                match &acc {
+                    Some(Ok(())) | Some(Err(SendError::SmtpPermanent(_))) => acc,
+                    _ => Some(
+                        attempt_one_host(mx_record, helo, command_timeout, require_tls, message)
+                            .await,
+                    ),
+                }
+            }
+        })
+        .await;
+    outcome.unwrap_or_else(|| {
+        Err(SendError::SmtpTransient(format!(
+            "no MX records returned for {}",
+            domain.as_str()
+        )))
+    })
+}
+
+async fn attempt_one_host(
+    mx_record: MxRecord,
+    helo: &HeloName,
+    command_timeout: Duration,
+    require_tls: bool,
+    message: Message,
+) -> Result<(), SendError> {
+    let host = mx_record.host.as_str().to_string();
+    let tls_params = TlsParameters::new(host.clone())
+        .map_err(|e| SendError::SmtpTransient(format!("TLS params for {host}: {e}")))?;
+    let tls = match require_tls {
+        true => Tls::Required(tls_params),
+        false => Tls::Opportunistic(tls_params),
+    };
+    let transport: AsyncSmtpTransport<Tokio1Executor> =
+        AsyncSmtpTransport::<Tokio1Executor>::builder_dangerous(&host)
+            .port(25)
+            .tls(tls)
+            .hello_name(ClientId::Domain(helo.as_str().to_string()))
+            .timeout(Some(command_timeout))
+            .build();
+    run_send(&transport, message).await
+}
+
+fn classify_smtp_error(e: SmtpError) -> SendError {
+    match () {
+        _ if e.is_permanent() => SendError::SmtpPermanent(e.to_string()),
+        _ if e.is_timeout() => SendError::Timeout,
+        _ => SendError::SmtpTransient(e.to_string()),
+    }
+}

crates/tranquil-comms/src/email/types.rs

@@ -0,0 +1,291 @@
+use std::path::PathBuf;
+
+#[derive(Debug, thiserror::Error)]
+pub enum ParseError {
+    #[error("empty value")]
+    Empty,
+    #[error("invalid character {0:?}")]
+    InvalidChar(char),
+    #[error("zero {0}")]
+    Zero(&'static str),
+    #[error("invalid TLS mode {0:?}")]
+    InvalidTlsMode(String),
+}
+
+fn parse_token(raw: &str, lowercase: bool, strip_trailing_dot: bool) -> Result<String, ParseError> {
+    let mut s = raw.trim();
+    if strip_trailing_dot {
+        s = s.trim_end_matches('.');
+    }
+    match s {
+        "" => Err(ParseError::Empty),
+        _ if s.chars().any(char::is_whitespace) => Err(ParseError::InvalidChar(' ')),
+        _ => Ok(match lowercase {
+            true => s.to_lowercase(),
+            false => s.to_string(),
+        }),
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct SmtpHost(String);
+
+impl SmtpHost {
+    pub fn parse(raw: &str) -> Result<Self, ParseError> {
+        parse_token(raw, true, false).map(Self)
+    }
+
+    pub fn as_str(&self) -> &str {
+        &self.0
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub struct SmtpPort(u16);
+
+impl SmtpPort {
+    pub fn parse(raw: u16) -> Result<Self, ParseError> {
+        match raw {
+            0 => Err(ParseError::Zero("smtp port")),
+            n => Ok(Self(n)),
+        }
+    }
+
+    pub fn as_u16(self) -> u16 {
+        self.0
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct HeloName(String);
+
+impl HeloName {
+    pub fn parse(raw: &str) -> Result<Self, ParseError> {
+        parse_token(raw, false, false).map(Self)
+    }
+
+    pub fn as_str(&self) -> &str {
+        &self.0
+    }
+
+    pub fn into_inner(self) -> String {
+        self.0
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct EmailDomain(String);
+
+impl EmailDomain {
+    pub fn parse(raw: &str) -> Result<Self, ParseError> {
+        parse_token(raw, true, true).map(Self)
+    }
+
+    pub fn as_str(&self) -> &str {
+        &self.0
+    }
+
+    pub fn into_inner(self) -> String {
+        self.0
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct MxHost(String);
+
+impl MxHost {
+    pub fn parse(raw: &str) -> Result<Self, ParseError> {
+        parse_token(raw, true, true).map(Self)
+    }
+
+    pub fn as_str(&self) -> &str {
+        &self.0
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct MxPriority(u16);
+
+impl MxPriority {
+    pub fn new(value: u16) -> Self {
+        Self(value)
+    }
+
+    pub fn as_u16(self) -> u16 {
+        self.0
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct MxRecord {
+    pub priority: MxPriority,
+    pub host: MxHost,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct DkimSelector(String);
+
+impl DkimSelector {
+    pub fn parse(raw: &str) -> Result<Self, ParseError> {
+        let trimmed = raw.trim();
+        let valid = !trimmed.is_empty() && trimmed.split('.').all(valid_subdomain);
+        match valid {
+            true => Ok(Self(trimmed.to_string())),
+            false => Err(ParseError::InvalidChar('?')),
+        }
+    }
+
+    pub fn into_inner(self) -> String {
+        self.0
+    }
+}
+
+fn valid_subdomain(seg: &str) -> bool {
+    let starts_alnum = seg
+        .chars()
+        .next()
+        .is_some_and(|c| c.is_ascii_alphanumeric());
+    let ends_alnum = seg
+        .chars()
+        .next_back()
+        .is_some_and(|c| c.is_ascii_alphanumeric());
+    let body_ok = seg.chars().all(|c| c.is_ascii_alphanumeric() || c == '-');
+    starts_alnum && ends_alnum && body_ok
+}
+
+#[derive(Debug, Clone)]
+pub struct DkimKeyPath(PathBuf);
+
+impl DkimKeyPath {
+    pub fn parse(raw: &str) -> Result<Self, ParseError> {
+        let trimmed = raw.trim();
+        match trimmed.is_empty() {
+            true => Err(ParseError::Empty),
+            false => Ok(Self(PathBuf::from(trimmed))),
+        }
+    }
+
+    pub fn as_path(&self) -> &std::path::Path {
+        &self.0
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct SmtpUsername(String);
+
+impl SmtpUsername {
+    pub fn parse(raw: &str) -> Result<Self, ParseError> {
+        match raw.is_empty() {
+            true => Err(ParseError::Empty),
+            false => Ok(Self(raw.to_string())),
+        }
+    }
+
+    pub fn into_inner(self) -> String {
+        self.0
+    }
+}
+
+#[derive(Clone)]
+pub struct SmtpPassword(secrecy::SecretString);
+
+impl SmtpPassword {
+    pub fn parse(raw: &str) -> Result<Self, ParseError> {
+        match raw.is_empty() {
+            true => Err(ParseError::Empty),
+            false => Ok(Self(secrecy::SecretString::from(raw.to_string()))),
+        }
+    }
+
+    pub fn expose(&self) -> &str {
+        use secrecy::ExposeSecret;
+        self.0.expose_secret()
+    }
+}
+
+impl std::fmt::Debug for SmtpPassword {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str("SmtpPassword(***)")
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum TlsMode {
+    Implicit,
+    Starttls,
+    None,
+}
+
+impl TlsMode {
+    pub fn parse(raw: &str) -> Result<Self, ParseError> {
+        match raw.to_ascii_lowercase().as_str() {
+            "implicit" => Ok(Self::Implicit),
+            "starttls" => Ok(Self::Starttls),
+            "none" => Ok(Self::None),
+            other => Err(ParseError::InvalidTlsMode(other.to_string())),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn smtp_host_lowercases_and_trims() {
+        let h = SmtpHost::parse("  SMTP.NEL.PET  ").unwrap();
+        assert_eq!(h.as_str(), "smtp.nel.pet");
+    }
+
+    #[test]
+    fn smtp_host_rejects_whitespace() {
+        assert!(SmtpHost::parse("a b").is_err());
+    }
+
+    #[test]
+    fn smtp_host_rejects_empty() {
+        assert!(SmtpHost::parse("").is_err());
+        assert!(SmtpHost::parse("   ").is_err());
+    }
+
+    #[test]
+    fn smtp_port_rejects_zero() {
+        assert!(SmtpPort::parse(0).is_err());
+        assert_eq!(SmtpPort::parse(587).unwrap().as_u16(), 587);
+    }
+
+    #[test]
+    fn email_domain_strips_trailing_dot() {
+        assert_eq!(EmailDomain::parse("Nel.pet.").unwrap().as_str(), "nel.pet");
+    }
+
+    #[test]
+    fn dkim_selector_validates() {
+        assert!(DkimSelector::parse("default").is_ok());
+        assert!(DkimSelector::parse("s1.nel.pet").is_ok());
+        assert!(DkimSelector::parse("s2024-q1").is_ok());
+        assert!(DkimSelector::parse("mailo-2024.nel.pet").is_ok());
+        assert!(DkimSelector::parse("a-b").is_ok());
+        assert!(DkimSelector::parse("").is_err());
+        assert!(DkimSelector::parse("a..b").is_err());
+        assert!(DkimSelector::parse("-leading").is_err());
+        assert!(DkimSelector::parse("trailing-").is_err());
+        assert!(DkimSelector::parse("s_under").is_err());
+    }
+
+    #[test]
+    fn tls_mode_parses_known_modes() {
+        assert_eq!(TlsMode::parse("STARTTLS").unwrap(), TlsMode::Starttls);
+        assert_eq!(TlsMode::parse("implicit").unwrap(), TlsMode::Implicit);
+        assert_eq!(TlsMode::parse("none").unwrap(), TlsMode::None);
+        assert!(TlsMode::parse("garbage").is_err());
+    }
+
+    #[test]
+    fn smtp_password_redacts_in_debug() {
+        let p = SmtpPassword::parse("hunter2").unwrap();
+        let dbg = format!("{:?}", p);
+        assert_eq!(dbg, "SmtpPassword(***)");
+        assert!(!dbg.contains("hunter2"));
+    }
+}

crates/tranquil-comms/src/lib.rs

@@ -1,13 +1,15 @@
+pub mod email;
 mod locale;
 mod sender;
 mod types;
 
+pub use email::EmailSender;
 pub use locale::{
     DEFAULT_LOCALE, NotificationStrings, VALID_LOCALES, format_message, get_strings,
     validate_locale,
 };
 pub use sender::{
-    CommsSender, DiscordSender, EmailSender, SendError, SignalSender, TelegramSender,
-    is_valid_phone_number, is_valid_signal_username, mime_encode_header, sanitize_header_value,
+    CommsSender, DiscordSender, SendError, SignalSender, TelegramSender, is_valid_phone_number,
+    is_valid_signal_username,
 };
 pub use types::{CommsChannel, CommsStatus, CommsType, NewComms, QueuedComms};

crates/tranquil-comms/src/locale.rs

@@ -1,5 +1,5 @@
 pub const DEFAULT_LOCALE: &str = "en";
-pub const VALID_LOCALES: &[&str] = &["en", "zh", "ja", "ko", "sv", "fi"];
+pub const VALID_LOCALES: &[&str] = &["en", "zh", "ja", "ko", "sv", "fi", "fr"];
 
 pub fn validate_locale(locale: &str) -> &str {
     if VALID_LOCALES.contains(&locale) {
@@ -44,6 +44,7 @@ pub fn get_strings(locale: &str) -> &'static NotificationStrings {
         "ko" => &STRINGS_KO,
         "sv" => &STRINGS_SV,
         "fi" => &STRINGS_FI,
+        "fr" => &STRINGS_FR,
         _ => &STRINGS_EN,
     }
 }
@@ -216,6 +217,34 @@ static STRINGS_FI: NotificationStrings = NotificationStrings {
     channel_verification_body: "Vahvistuskoodisi on:\n{code}\n\nTai vahvista suoraan:\n{verify_link}",
 };
 
+static STRINGS_FR: NotificationStrings = NotificationStrings {
+    welcome_subject: "Bienvenue sur {hostname}",
+    welcome_body: "Bienvenue sur {hostname} !\n\nVotre identifiant est : @{handle}\n\nMerci de nous avoir rejoint.",
+    password_reset_subject: "Réinitialisation du mot de passe - {hostname}",
+    password_reset_body: "Bonjour @{handle},\n\nVotre code de réinitialisation du mot de passe est : {code}\n\nCe code expirera dans 10 minutes.\n\nSi vous n'avez pas demandé cela, veuillez ignorer ce message.",
+    email_update_subject: "Confirmer votre nouvelle adresse e-mail - {hostname}",
+    email_update_body: "Bonjour @{handle},\n\nVotre code de vérification est :\n{code}\n\nCopiez le code ci-dessus et saisissez-le ici :\n{verify_page}\n\nCe code expirera dans 10 minutes.\n\nOu si vous aimez vivre dangereusement :\n{verify_link}\n\nSi vous n'avez pas demandé cela, veuillez ignorer cet e-mail.",
+    short_token_body: "Bonjour @{handle},\n\nVotre code de vérification est :\n{code}\n\nCe code expirera dans 15 minutes.\n\nSi vous n'avez pas demandé cela, veuillez ignorer cet e-mail.",
+    account_deletion_subject: "Demande de suppression de compte - {hostname}",
+    account_deletion_body: "Bonjour @{handle},\n\nVotre code de confirmation de suppression de compte est : {code}\n\nCe code expirera dans 10 minutes.\n\nSi vous n'avez pas demandé cela, sécurisez votre compte immédiatement.",
+    plc_operation_subject: "{hostname} - Jeton d'opération PLC",
+    plc_operation_body: "Bonjour @{handle},\n\nVous avez demandé à signer une opération PLC pour votre compte.\n\nVotre jeton de vérification est : {token}\n\nCe jeton expirera dans 10 minutes.\n\nSi vous n'avez pas demandé cela, vous pouvez ignorer ce message en toute sécurité.",
+    two_factor_code_subject: "Vérification de connexion - {hostname}",
+    two_factor_code_body: "Bonjour @{handle},\n\nVotre code de vérification de connexion est : {code}\n\nCe code expirera dans 10 minutes.\n\nSi vous n'avez pas demandé cela, sécurisez votre compte immédiatement.",
+    passkey_recovery_subject: "Récupération de compte - {hostname}",
+    passkey_recovery_body: "Bonjour @{handle},\n\nVous avez demandé la récupération de votre compte à clé d'accès uniquement.\n\nCliquez sur le lien ci-dessous pour définir un mot de passe temporaire et retrouver l'accès :\n{url}\n\nCe lien expirera dans 1 heure.\n\nSi vous n'avez pas demandé cela, veuillez ignorer ce message. Votre compte reste sécurisé.",
+    signup_verification_subject: "Vérifier votre compte - {hostname}",
+    signup_verification_body: "Bienvenue ! Votre code de vérification est :\n{code}\n\nCopiez le code ci-dessus et saisissez-le ici :\n{verify_page}\n\nCe code expirera dans 30 minutes.\n\nOu si vous aimez vivre dangereusement :\n{verify_link}\n\nSi vous n'avez pas créé de compte sur {hostname}, veuillez ignorer ce message.",
+    legacy_login_subject: "Alerte de sécurité : Connexion classique détectée - {hostname}",
+    legacy_login_body: "Bonjour @{handle},\n\nUne connexion à votre compte a été détectée via une application classique (comme Bluesky) qui ne prend pas en charge la vérification TOTP.\n\nDétails :\n- Date : {timestamp}\n- Adresse IP : {ip}\n\nVotre protection TOTP a été contournée pour cette connexion. La session dispose de permissions limitées pour les opérations sensibles.\n\nSi ce n'était pas vous :\n1. Changez votre mot de passe immédiatement\n2. Vérifiez vos sessions actives\n3. Envisagez de désactiver les connexions d'applications classiques dans vos paramètres de sécurité\n\nRestez vigilant,\n{hostname}",
+    migration_verification_subject: "Vérifier votre adresse e-mail - {hostname}",
+    migration_verification_body: "Bienvenue sur {hostname} !\n\nVotre compte a été migré avec succès. Pour finaliser la configuration, veuillez vérifier votre adresse e-mail.\n\nVotre code de vérification est :\n{code}\n\nCopiez le code ci-dessus et saisissez-le ici :\n{verify_page}\n\nCe code expirera dans 48 heures.\n\nOu si vous aimez vivre dangereusement :\n{verify_link}\n\nSi vous n'avez pas migré votre compte, veuillez ignorer cet e-mail.",
+    channel_verified_subject: "Canal de notification vérifié - {hostname}",
+    channel_verified_body: "Bonjour {handle},\n\n{channel} a été vérifié comme canal de notification pour votre compte sur {hostname}.",
+    channel_verification_subject: "Vérifier votre canal - {hostname}",
+    channel_verification_body: "Votre code de vérification est :\n{code}\n\nOu vérifiez directement :\n{verify_link}",
+};
+
 pub fn format_message(template: &str, vars: &[(&str, &str)]) -> String {
     vars.iter()
         .fold(template.to_string(), |result, (key, value)| {
@@ -233,6 +262,9 @@ mod tests {
         assert_eq!(validate_locale("zh"), "zh");
         assert_eq!(validate_locale("ja"), "ja");
         assert_eq!(validate_locale("ko"), "ko");
+        assert_eq!(validate_locale("sv"), "sv");
+        assert_eq!(validate_locale("fi"), "fi");
+        assert_eq!(validate_locale("fr"), "fr");
         assert_eq!(validate_locale("invalid"), DEFAULT_LOCALE);
         assert_eq!(validate_locale(""), DEFAULT_LOCALE);
     }
@@ -252,5 +284,9 @@ mod tests {
         let zh = get_strings("zh");
         assert!(zh.welcome_subject.contains("{hostname}"));
         assert!(zh.welcome_body.contains("欢迎"));
+
+        let fr = get_strings("fr");
+        assert!(fr.welcome_subject.contains("{hostname}"));
+        assert!(fr.welcome_body.contains("Bienvenue"));
     }
 }

crates/tranquil-comms/src/sender.rs

@@ -1,11 +1,7 @@
 use async_trait::async_trait;
-use base64::{Engine, engine::general_purpose::STANDARD as BASE64};
 use reqwest::Client;
 use serde_json::json;
-use std::process::Stdio;
 use std::time::Duration;
-use tokio::io::AsyncWriteExt;
-use tokio::process::Command;
 
 use super::types::{CommsChannel, QueuedComms};
 
@@ -21,25 +17,51 @@ pub trait CommsSender: Send + Sync {
 
 #[derive(Debug, thiserror::Error)]
 pub enum SendError {
-    #[error("Failed to spawn {command}: {source}")]
-    ProcessSpawn {
-        command: String,
-        source: std::io::Error,
-    },
-    #[error("{command} exited with non-zero status: {detail}")]
-    ProcessFailed { command: String, detail: String },
     #[error("Channel not configured: {0:?}")]
     NotConfigured(CommsChannel),
-    #[error("External service error: {0}")]
-    ExternalService(String),
+    #[error("Email configuration invalid: {0}")]
+    ConfigInvalid(String),
     #[error("Invalid recipient format: {0}")]
     InvalidRecipient(String),
+    #[error("Message construction failed: {0}")]
+    MessageBuild(String),
+    #[error("transient DNS lookup failure: {0}")]
+    DnsTransient(String),
+    #[error("permanent DNS lookup failure: {0}")]
+    DnsPermanent(String),
+    #[error("SMTP transient error: {0}")]
+    SmtpTransient(String),
+    #[error("SMTP permanent error: {0}")]
+    SmtpPermanent(String),
+    #[error("DKIM signing failed: {0}")]
+    DkimSign(String),
+    #[error("External service error: {0}")]
+    ExternalService(String),
     #[error("Request timeout")]
     Timeout,
     #[error("Max retries exceeded: {0}")]
     MaxRetriesExceeded(String),
 }
 
+impl SendError {
+    pub fn is_permanent(&self) -> bool {
+        match self {
+            Self::SmtpPermanent(_)
+            | Self::DnsPermanent(_)
+            | Self::InvalidRecipient(_)
+            | Self::MessageBuild(_)
+            | Self::DkimSign(_)
+            | Self::ConfigInvalid(_) => true,
+            Self::SmtpTransient(_)
+            | Self::DnsTransient(_)
+            | Self::Timeout
+            | Self::ExternalService(_)
+            | Self::MaxRetriesExceeded(_)
+            | Self::NotConfigured(_) => false,
+        }
+    }
+}
+
 fn create_http_client() -> Client {
     Client::builder()
         .timeout(Duration::from_secs(HTTP_TIMEOUT_SECS))
@@ -100,19 +122,6 @@ where
     ))
 }
 
-pub fn sanitize_header_value(value: &str) -> String {
-    value.replace(['\r', '\n'], " ").trim().to_string()
-}
-
-pub fn mime_encode_header(value: &str) -> String {
-    if value.is_ascii() {
-        sanitize_header_value(value)
-    } else {
-        let sanitized = sanitize_header_value(value);
-        format!("=?UTF-8?B?{}?=", BASE64.encode(sanitized.as_bytes()))
-    }
-}
-
 pub fn escape_html(text: &str) -> String {
     text.replace('&', "&")
         .replace('<', "&lt;")
@@ -135,93 +144,6 @@ pub fn is_valid_signal_username(username: &str) -> bool {
     tranquil_signal::SignalUsername::parse(username).is_ok()
 }
 
-pub struct EmailSender {
-    from_address: String,
-    from_name: String,
-    sendmail_path: String,
-}
-
-impl EmailSender {
-    pub fn new(from_address: String, from_name: String, sendmail_path: String) -> Self {
-        Self {
-            from_address,
-            from_name,
-            sendmail_path,
-        }
-    }
-
-    pub fn from_config(cfg: &tranquil_config::TranquilConfig) -> Option<Self> {
-        let from_address = cfg.email.from_address.clone()?;
-        let from_name = cfg.email.from_name.clone();
-        let sendmail_path = cfg.email.sendmail_path.clone();
-        Some(Self::new(from_address, from_name, sendmail_path))
-    }
-
-    pub fn format_email(&self, notification: &QueuedComms) -> String {
-        let subject = mime_encode_header(notification.subject.as_deref().unwrap_or("Notification"));
-        let recipient = sanitize_header_value(&notification.recipient);
-        let from_header = if self.from_name.is_empty() {
-            self.from_address.clone()
-        } else {
-            format!(
-                "{} <{}>",
-                sanitize_header_value(&self.from_name),
-                self.from_address
-            )
-        };
-        format!(
-            "From: {}\r\nTo: {}\r\nSubject: {}\r\nContent-Type: text/plain; charset=utf-8\r\nMIME-Version: 1.0\r\n\r\n{}",
-            from_header, recipient, subject, notification.body
-        )
-    }
-}
-
-#[async_trait]
-impl CommsSender for EmailSender {
-    fn channel(&self) -> CommsChannel {
-        CommsChannel::Email
-    }
-
-    async fn send(&self, notification: &QueuedComms) -> Result<(), SendError> {
-        let email_content = self.format_email(notification);
-        let mut child = Command::new(&self.sendmail_path)
-            .arg("-t")
-            .arg("-oi")
-            .stdin(Stdio::piped())
-            .stdout(Stdio::piped())
-            .stderr(Stdio::piped())
-            .spawn()
-            .map_err(|e| SendError::ProcessSpawn {
-                command: self.sendmail_path.clone(),
-                source: e,
-            })?;
-        if let Some(mut stdin) = child.stdin.take() {
-            stdin
-                .write_all(email_content.as_bytes())
-                .await
-                .map_err(|e| SendError::ProcessSpawn {
-                    command: self.sendmail_path.clone(),
-                    source: e,
-                })?;
-        }
-        let output = child
-            .wait_with_output()
-            .await
-            .map_err(|e| SendError::ProcessSpawn {
-                command: self.sendmail_path.clone(),
-                source: e,
-            })?;
-        if !output.status.success() {
-            let stderr = String::from_utf8_lossy(&output.stderr);
-            return Err(SendError::ProcessFailed {
-                command: self.sendmail_path.clone(),
-                detail: stderr.to_string(),
-            });
-        }
-        Ok(())
-    }
-}
-
 const DISCORD_API_BASE: &str = "https://discord.com/api/v10";
 
 #[derive(Clone)]
@@ -610,3 +532,28 @@ impl CommsSender for SignalSender {
         ))
     }
 }
+
+#[cfg(test)]
+mod is_permanent_matrix {
+    use super::{CommsChannel, SendError};
+
+    #[test]
+    fn permanent_variants_are_permanent() {
+        assert!(SendError::SmtpPermanent("x".into()).is_permanent());
+        assert!(SendError::DnsPermanent("x".into()).is_permanent());
+        assert!(SendError::InvalidRecipient("x".into()).is_permanent());
+        assert!(SendError::MessageBuild("x".into()).is_permanent());
+        assert!(SendError::DkimSign("x".into()).is_permanent());
+        assert!(SendError::ConfigInvalid("x".into()).is_permanent());
+    }
+
+    #[test]
+    fn transient_variants_are_not_permanent() {
+        assert!(!SendError::SmtpTransient("x".into()).is_permanent());
+        assert!(!SendError::DnsTransient("x".into()).is_permanent());
+        assert!(!SendError::Timeout.is_permanent());
+        assert!(!SendError::ExternalService("x".into()).is_permanent());
+        assert!(!SendError::MaxRetriesExceeded("x".into()).is_permanent());
+        assert!(!SendError::NotConfigured(CommsChannel::Email).is_permanent());
+    }
+}

crates/tranquil-comms/tests/email_smtp.rs

@@ -0,0 +1,158 @@
+use std::time::Duration;
+
+use chrono::Utc;
+use lettre::message::Mailbox;
+use lettre::transport::smtp::AsyncSmtpTransport;
+use lettre::transport::smtp::extension::ClientId;
+use tokio::io::{AsyncBufReadExt, AsyncWriteExt, BufReader};
+use tokio::net::{TcpListener, TcpStream};
+use tranquil_comms::email::transport::SendMode;
+use tranquil_comms::email::{EmailSender, types::HeloName};
+use tranquil_comms::{CommsChannel, CommsSender, CommsStatus, CommsType, QueuedComms, SendError};
+use uuid::Uuid;
+
+fn fixture(recipient: &str, subject: &str, body: &str) -> QueuedComms {
+    QueuedComms {
+        id: Uuid::new_v4(),
+        user_id: None,
+        channel: CommsChannel::Email,
+        comms_type: CommsType::Welcome,
+        status: CommsStatus::Pending,
+        recipient: recipient.to_string(),
+        subject: Some(subject.to_string()),
+        body: body.to_string(),
+        metadata: None,
+        attempts: 0,
+        max_attempts: 3,
+        last_error: None,
+        created_at: Utc::now(),
+        updated_at: Utc::now(),
+        scheduled_for: Utc::now(),
+        processed_at: None,
+    }
+}
+
+fn build_smarthost_sender(host: &str, port: u16) -> EmailSender {
+    build_smarthost_sender_with_total_timeout(host, port, Duration::from_secs(10))
+}
+
+fn build_smarthost_sender_with_total_timeout(
+    host: &str,
+    port: u16,
+    total_timeout: Duration,
+) -> EmailSender {
+    let from: Mailbox = "Tranquil Test <noreply@nel.pet>".parse().unwrap();
+    let helo = HeloName::parse("mta.nel.pet").unwrap();
+    let transport = AsyncSmtpTransport::<lettre::Tokio1Executor>::builder_dangerous(host)
+        .port(port)
+        .hello_name(ClientId::Domain(helo.into_inner()))
+        .timeout(Some(Duration::from_secs(5)))
+        .build();
+    EmailSender::new(
+        from,
+        SendMode::Smarthost {
+            transport: Box::new(transport),
+            total_timeout,
+        },
+        None,
+    )
+}
+
+async fn drive_stub(stream: TcpStream, rcpt_response: &'static [u8]) -> std::io::Result<()> {
+    let (read, mut write) = stream.into_split();
+    let mut reader = BufReader::new(read);
+    write.write_all(b"220 stub ESMTP\r\n").await?;
+    let mut line = String::new();
+    loop {
+        line.clear();
+        let n = reader.read_line(&mut line).await?;
+        if n == 0 {
+            return Ok(());
+        }
+        let upper = line.to_ascii_uppercase();
+        let response: &[u8] = match upper.split_whitespace().next() {
+            Some("EHLO") | Some("HELO") => b"250-stub\r\n250 SIZE 10240000\r\n",
+            Some("MAIL") => b"250 OK\r\n",
+            Some("RCPT") => rcpt_response,
+            Some("DATA") => b"354 end with .\r\n",
+            Some("RSET") => b"250 OK\r\n",
+            Some("QUIT") => b"221 bye\r\n",
+            _ => b"500 unknown\r\n",
+        };
+        write.write_all(response).await?;
+        if upper.starts_with("QUIT") {
+            return Ok(());
+        }
+    }
+}
+
+async fn spawn_stub(rcpt_response: &'static [u8]) -> u16 {
+    let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();
+    let port = listener.local_addr().unwrap().port();
+    tokio::spawn(async move {
+        let (stream, _) = listener.accept().await.unwrap();
+        let _ = drive_stub(stream, rcpt_response).await;
+    });
+    port
+}
+
+#[tokio::test]
+async fn rcpt_550_classifies_as_smtp_permanent() {
+    let port = spawn_stub(b"550 5.1.1 user unknown\r\n").await;
+    let sender = build_smarthost_sender("127.0.0.1", port);
+    let result = sender.send(&fixture("nel@nel.pet", "x", "x")).await;
+    match result {
+        Err(SendError::SmtpPermanent(_)) => {}
+        other => panic!("expected SmtpPermanent, got {other:?}"),
+    }
+}
+
+#[tokio::test]
+async fn rcpt_421_classifies_as_smtp_transient() {
+    let port = spawn_stub(b"421 4.7.0 try again later\r\n").await;
+    let sender = build_smarthost_sender("127.0.0.1", port);
+    let result = sender.send(&fixture("nel@nel.pet", "x", "x")).await;
+    match result {
+        Err(SendError::SmtpTransient(_)) => {}
+        other => panic!("expected SmtpTransient, got {other:?}"),
+    }
+}
+
+#[tokio::test]
+async fn invalid_recipient_classifies_as_invalid_recipient() {
+    let port = spawn_stub(b"250 OK\r\n").await;
+    let sender = build_smarthost_sender("127.0.0.1", port);
+    let result = sender.send(&fixture("not-an-address", "x", "x")).await;
+    match result {
+        Err(SendError::InvalidRecipient(_)) => {}
+        other => panic!("expected InvalidRecipient, got {other:?}"),
+    }
+}
+
+async fn spawn_silent_stub() -> u16 {
+    let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();
+    let port = listener.local_addr().unwrap().port();
+    tokio::spawn(async move {
+        let (_stream, _) = listener.accept().await.unwrap();
+        std::future::pending::<()>().await;
+    });
+    port
+}
+
+#[tokio::test]
+async fn smarthost_silent_relay_hits_total_timeout() {
+    let port = spawn_silent_stub().await;
+    let sender =
+        build_smarthost_sender_with_total_timeout("127.0.0.1", port, Duration::from_millis(500));
+    let start = std::time::Instant::now();
+    let result = sender.send(&fixture("nel@nel.pet", "x", "x")).await;
+    let elapsed = start.elapsed();
+    match result {
+        Err(SendError::Timeout) => {}
+        other => panic!("expected Timeout, got {other:?}"),
+    }
+    assert!(
+        elapsed < Duration::from_secs(2),
+        "send returned in {elapsed:?}, expected close to 500ms total_timeout"
+    );
+}

crates/tranquil-config/src/lib.rs

@@ -5,6 +5,14 @@ use std::sync::OnceLock;
 
 static CONFIG: OnceLock<TranquilConfig> = OnceLock::new();
 
+const REMOVED_ENV_VARS: &[(&str, &str)] = &[(
+    "SENDMAIL_PATH",
+    "the sendmail-binary transport was replaced with native SMTP. \
+     Configure MAIL_SMARTHOST_HOST for relay delivery, or leave it unset to \
+     deliver directly via recipient MX records. See example.toml for the full \
+     MAIL_* surface.",
+)];
+
 /// Errors discovered during configuration validation.
 #[derive(Debug)]
 pub struct ConfigError {
@@ -83,8 +91,9 @@ pub fn ensure_test_defaults() {
 ///
 /// Precedence (highest to lowest):
 /// 1. Environment variables
-/// 2. TOML config file (if provided)
-/// 3. Built-in defaults
+/// 2. Toml config file passed as `config_path`, if provided
+/// 3. `/etc/tranquil-pds/config.toml` - hardcoded fallback, silently skipped if absent
+/// 4. Built-in defaults
 pub fn load(config_path: Option<&PathBuf>) -> Result<TranquilConfig, confique::Error> {
     let mut builder = TranquilConfig::builder().env();
     if let Some(path) = config_path {
@@ -95,6 +104,7 @@ pub fn load(config_path: Option<&PathBuf>) -> Result<TranquilConfig, confique::E
 
 // Root configuration
 #[derive(Debug, Config)]
+#[config(layer_attr(serde(deny_unknown_fields)))]
 pub struct TranquilConfig {
     #[config(nested)]
     pub server: ServerConfig,
@@ -132,9 +142,6 @@ pub struct TranquilConfig {
     #[config(nested)]
     pub telegram: TelegramConfig,
 
-    #[config(nested)]
-    pub signal: SignalConfig,
-
     #[config(nested)]
     pub notifications: NotificationConfig,
 
@@ -161,6 +168,14 @@ impl TranquilConfig {
     pub fn validate(&self, ignore_secrets: bool) -> Result<(), ConfigError> {
         let mut errors = Vec::new();
 
+        // -- removed config ---------------------------------------------------
+        errors.extend(
+            REMOVED_ENV_VARS
+                .iter()
+                .filter(|(var, _)| std::env::var_os(var).is_some())
+                .map(|(var, guidance)| format!("{var} is no longer supported: {guidance}")),
+        );
+
         // -- secrets ----------------------------------------------------------
         if !ignore_secrets && !self.secrets.allow_insecure && !cfg!(test) {
             if let Some(ref s) = self.secrets.jwt_secret {
@@ -209,6 +224,10 @@ impl TranquilConfig {
             }
         }
 
+        // -- email -----------------------------------------------------------
+        self.email
+            .validate(self.server.hostname_without_port(), &mut errors);
+
         // -- telegram ---------------------------------------------------------
         if self.telegram.bot_token.is_some() && self.telegram.webhook_secret.is_none() {
             errors.push(
@@ -237,6 +256,9 @@ impl TranquilConfig {
             }
         }
 
+        // -- tls --------------------------------------------------------------
+        self.server.tls.validate(&mut errors);
+
         // -- SSO providers ----------------------------------------------------
         self.validate_sso_provider("sso.github", &self.sso.github, &mut errors);
         self.validate_sso_provider("sso.google", &self.sso.google, &mut errors);
@@ -396,6 +418,7 @@ impl TranquilConfig {
 // ---------------------------------------------------------------------------
 
 #[derive(Debug, Config)]
+#[config(layer_attr(serde(deny_unknown_fields)))]
 pub struct ServerConfig {
     /// Public hostname of the PDS, such as `pds.example.com`.
     #[config(env = "PDS_HOSTNAME")]
@@ -435,6 +458,11 @@ pub struct ServerConfig {
     #[config(env = "DISABLE_RATE_LIMITING", default = false)]
     pub disable_rate_limiting: bool,
 
+    /// Skip the verified-comms-channel gate for login and record writes.
+    /// Please keep this off unless you're an invite-only PDS!
+    #[config(env = "DISABLE_ACCOUNT_VERIFICATION_GATE", default = false)]
+    pub disable_account_verification_gate: bool,
+
     /// List of additional banned words for handle validation.
     #[config(env = "PDS_BANNED_WORDS", parse_env = split_comma_list)]
     pub banned_words: Option<Vec<String>>,
@@ -458,6 +486,52 @@ pub struct ServerConfig {
     /// Maximum allowed number of preferences
     #[config(env = "MAX_PREFERENCES_COUNT", default = 1000)]
     pub max_preferences_count: usize,
+
+    /// If you're not altering TLS config, you don't have to worry about this.
+    /// This is the number of trusted reverse proxies in front of Tranquil.
+    /// We read the client IP used for rate limiting and device records this many hops
+    /// from the right of the X-Forwarded-For header.
+    /// When left unset, Tranquil will assume:
+    /// - 0, if the TLS termination is happening here on Tranquil via the TLS config
+    /// - 1, if the TLS termination *isn't* happening here.
+    #[config(env = "TRUSTED_PROXY_COUNT")]
+    pub trusted_proxy_count: Option<usize>,
+
+    #[config(nested)]
+    pub tls: TlsConfig,
+}
+
+#[derive(Debug, Config)]
+pub struct TlsConfig {
+    /// The path to the TLS cert chain.
+    /// If you set both this and `key_path`, the server terminates TLS itself rather than expecting
+    /// a reverse proxy to do it. The certificate and key reload on SIGHUP.
+    #[config(env = "TLS_CERT_PATH")]
+    pub cert_path: Option<String>,
+
+    /// Path to the TLS private key.
+    #[config(env = "TLS_KEY_PATH")]
+    pub key_path: Option<String>,
+}
+
+impl TlsConfig {
+    /// The certificate and key paths when both are configured.
+    pub fn material(&self) -> Option<(&str, &str)> {
+        match (self.cert_path.as_deref(), self.key_path.as_deref()) {
+            (Some(cert), Some(key)) => Some((cert, key)),
+            _ => None,
+        }
+    }
+
+    pub fn validate(&self, errors: &mut Vec<String>) {
+        if self.cert_path.is_some() != self.key_path.is_some() {
+            errors.push(
+                "server.tls.cert_path (TLS_CERT_PATH) and server.tls.key_path (TLS_KEY_PATH) \
+                 must both be set to enable app-level TLS, or both be unset"
+                    .to_string(),
+            );
+        }
+    }
 }
 
 impl ServerConfig {
@@ -492,6 +566,7 @@ impl ServerConfig {
 }
 
 #[derive(Debug, Config)]
+#[config(layer_attr(serde(deny_unknown_fields)))]
 pub struct FrontendConfig {
     /// Whether to enable the built in serving of the frontend.
     #[config(env = "FRONTEND_ENABLED", default = true)]
@@ -504,6 +579,7 @@ pub struct FrontendConfig {
 }
 
 #[derive(Debug, Config)]
+#[config(layer_attr(serde(deny_unknown_fields)))]
 pub struct DatabaseConfig {
     /// PostgreSQL connection URL.
     #[config(env = "DATABASE_URL")]
@@ -523,6 +599,7 @@ pub struct DatabaseConfig {
 }
 
 #[derive(Config)]
+#[config(layer_attr(serde(deny_unknown_fields)))]
 pub struct SecretsConfig {
     /// Secret used for signing JWTs. Must be at least 32 characters in
     /// production.
@@ -649,6 +726,7 @@ impl fmt::Display for RepoBackend {
 }
 
 #[derive(Debug, Config)]
+#[config(layer_attr(serde(deny_unknown_fields)))]
 pub struct StorageConfig {
     /// Storage backend: `filesystem` or `s3`.
     #[config(env = "BLOB_STORAGE_BACKEND", default = "filesystem")]
@@ -681,6 +759,7 @@ impl StorageConfig {
 }
 
 #[derive(Debug, Config)]
+#[config(layer_attr(serde(deny_unknown_fields)))]
 pub struct CacheConfig {
     /// Cache backend: `ripple` by default, or `valkey`.
     #[config(env = "CACHE_BACKEND", default = "ripple")]
@@ -695,6 +774,7 @@ pub struct CacheConfig {
 }
 
 #[derive(Debug, Config)]
+#[config(layer_attr(serde(deny_unknown_fields)))]
 pub struct PlcConfig {
     /// Base URL of the PLC directory.
     #[config(env = "PLC_DIRECTORY_URL", default = "https://plc.directory")]
@@ -714,6 +794,7 @@ pub struct PlcConfig {
 }
 
 #[derive(Debug, Config)]
+#[config(layer_attr(serde(deny_unknown_fields)))]
 pub struct FirehoseConfig {
     /// Size of the in-memory broadcast buffer for firehose events.
     #[config(env = "FIREHOSE_BUFFER_SIZE", default = 10000)]
@@ -724,10 +805,6 @@ pub struct FirehoseConfig {
     #[config(env = "FIREHOSE_BACKFILL_HOURS", default = 72)]
     pub backfill_hours: i64,
 
-    /// Maximum number of lagged events before disconnecting a slow consumer.
-    #[config(env = "FIREHOSE_MAX_LAG", default = 5000)]
-    pub max_lag: u64,
-
     /// Maximum concurrent full-repo exports, eg. getRepo without `since`.
     #[config(env = "MAX_CONCURRENT_REPO_EXPORTS", default = 4)]
     pub max_concurrent_repo_exports: usize,
@@ -748,6 +825,7 @@ impl FirehoseConfig {
 }
 
 #[derive(Debug, Config)]
+#[config(layer_attr(serde(deny_unknown_fields)))]
 pub struct EmailConfig {
     /// Sender email address. When unset, email sending is disabled.
     #[config(env = "MAIL_FROM_ADDRESS")]
@@ -757,12 +835,285 @@ pub struct EmailConfig {
     #[config(env = "MAIL_FROM_NAME", default = "Tranquil PDS")]
     pub from_name: String,
 
-    /// Path to the `sendmail` binary.
-    #[config(env = "SENDMAIL_PATH", default = "/usr/sbin/sendmail")]
-    pub sendmail_path: String,
+    /// HELO/EHLO name announced to remote SMTP servers. Applies to both
+    /// smarthost and direct-MX modes. Defaults to the server hostname.
+    #[config(env = "MAIL_HELO_NAME")]
+    pub helo_name: Option<String>,
+
+    #[config(nested)]
+    pub smarthost: SmarthostConfig,
+
+    #[config(nested)]
+    pub direct_mx: DirectMxConfig,
+
+    #[config(nested)]
+    pub dkim: DkimConfig,
+}
+
+impl EmailConfig {
+    pub fn validate(&self, server_hostname: &str, errors: &mut Vec<String>) {
+        match self.smarthost.tls.to_ascii_lowercase().as_str() {
+            "implicit" | "starttls" => {}
+            "none" => {
+                if self.smarthost.password.is_some() {
+                    errors.push(
+                        "email.smarthost.tls = \"none\" with email.smarthost.password set \
+                         would transmit credentials in plaintext; use \"starttls\" or \"implicit\""
+                            .to_string(),
+                    );
+                }
+            }
+            other => errors.push(format!(
+                "email.smarthost.tls must be \"implicit\", \"starttls\", or \"none\", got \"{other}\""
+            )),
+        }
+
+        let smarthost_host_set = self
+            .smarthost
+            .host
+            .as_deref()
+            .is_some_and(|h| !h.is_empty());
+        let username_set = self.smarthost.username.is_some();
+        let password_set = self.smarthost.password.is_some();
+        if !smarthost_host_set && (username_set || password_set) {
+            errors.push(
+                "email.smarthost.username or email.smarthost.password is set but \
+                 email.smarthost.host is empty; credentials would be silently ignored"
+                    .to_string(),
+            );
+        }
+        if smarthost_host_set && username_set != password_set {
+            errors.push(
+                "email.smarthost.username and email.smarthost.password must both be set or \
+                 both unset; otherwise authentication would silently degrade to anonymous"
+                    .to_string(),
+            );
+        }
+
+        if self.smarthost.command_timeout_secs == 0 {
+            errors.push("email.smarthost.command_timeout_secs must be at least 1".to_string());
+        }
+        if self.smarthost.total_timeout_secs == 0 {
+            errors.push("email.smarthost.total_timeout_secs must be at least 1".to_string());
+        }
+        if self.smarthost.pool_size == 0 {
+            errors.push("email.smarthost.pool_size must be at least 1".to_string());
+        }
+
+        if self.direct_mx.max_concurrent_sends == 0 {
+            errors.push("email.direct_mx.max_concurrent_sends must be at least 1".to_string());
+        }
+        if self.direct_mx.command_timeout_secs == 0 {
+            errors.push("email.direct_mx.command_timeout_secs must be at least 1".to_string());
+        }
+        if self.direct_mx.total_timeout_secs == 0 {
+            errors.push("email.direct_mx.total_timeout_secs must be at least 1".to_string());
+        }
+
+        let dkim_set = self.dkim.selector.is_some()
+            || self.dkim.domain.is_some()
+            || self.dkim.private_key_path.is_some();
+        if dkim_set {
+            if self.dkim.selector.is_none() {
+                errors
+                    .push("email.dkim.selector is required when any DKIM field is set".to_string());
+            }
+            if self.dkim.domain.is_none() {
+                errors.push("email.dkim.domain is required when any DKIM field is set".to_string());
+            }
+            if self.dkim.private_key_path.is_none() {
+                errors.push(
+                    "email.dkim.private_key_path is required when any DKIM field is set"
+                        .to_string(),
+                );
+            }
+        }
+
+        let Some(from_address) = self.from_address.as_deref().filter(|s| !s.is_empty()) else {
+            return;
+        };
+
+        if !looks_like_email_address(from_address) {
+            errors.push(format!(
+                "email.from_address {from_address:?} is not a valid email address"
+            ));
+        }
+        if self.from_name.chars().any(|c| c.is_control()) {
+            errors.push("email.from_name must not contain control characters".to_string());
+        }
+
+        let helo_raw = self
+            .helo_name
+            .as_deref()
+            .map(str::to_string)
+            .unwrap_or_else(|| server_hostname.to_string());
+        if !is_non_whitespace_token(&helo_raw) {
+            errors.push(format!(
+                "email HELO name {helo_raw:?} must be non-empty and contain no whitespace"
+            ));
+        }
+
+        if smarthost_host_set {
+            let host = self.smarthost.host.as_deref().unwrap_or("");
+            if !is_non_whitespace_token(host) {
+                errors.push(format!(
+                    "email.smarthost.host {host:?} must contain no whitespace"
+                ));
+            }
+            if self.smarthost.port == 0 {
+                errors.push("email.smarthost.port must be non-zero".to_string());
+            }
+            if let Some(u) = self.smarthost.username.as_deref()
+                && u.is_empty()
+            {
+                errors.push("email.smarthost.username must be non-empty".to_string());
+            }
+            if let Some(p) = self.smarthost.password.as_deref()
+                && p.is_empty()
+            {
+                errors.push("email.smarthost.password must be non-empty".to_string());
+            }
+        }
+
+        if let Some(selector) = self.dkim.selector.as_deref()
+            && !is_valid_dkim_selector(selector)
+        {
+            errors.push(format!(
+                "email.dkim.selector {selector:?} must be valid subdomain syntax"
+            ));
+        }
+        if let Some(domain) = self.dkim.domain.as_deref()
+            && !is_non_whitespace_token(domain)
+        {
+            errors.push(format!(
+                "email.dkim.domain {domain:?} must be non-empty and contain no whitespace"
+            ));
+        }
+        if let Some(key_path) = self.dkim.private_key_path.as_deref()
+            && key_path.trim().is_empty()
+        {
+            errors.push("email.dkim.private_key_path must be non-empty".to_string());
+        }
+    }
+}
+
+fn looks_like_email_address(s: &str) -> bool {
+    let trimmed = s.trim();
+    if trimmed.is_empty() || trimmed.chars().any(char::is_whitespace) {
+        return false;
+    }
+    let mut parts = trimmed.split('@');
+    let local = parts.next().unwrap_or("");
+    let domain = parts.next().unwrap_or("");
+    parts.next().is_none() && !local.is_empty() && !domain.is_empty() && domain.contains('.')
+}
+
+fn is_non_whitespace_token(s: &str) -> bool {
+    let trimmed = s.trim();
+    !trimmed.is_empty() && !trimmed.chars().any(char::is_whitespace)
+}
+
+fn is_valid_dkim_selector(s: &str) -> bool {
+    let trimmed = s.trim();
+    !trimmed.is_empty()
+        && trimmed.split('.').all(|seg| {
+            let starts_alnum = seg
+                .chars()
+                .next()
+                .is_some_and(|c| c.is_ascii_alphanumeric());
+            let ends_alnum = seg
+                .chars()
+                .next_back()
+                .is_some_and(|c| c.is_ascii_alphanumeric());
+            let body_ok = seg.chars().all(|c| c.is_ascii_alphanumeric() || c == '-');
+            starts_alnum && ends_alnum && body_ok
+        })
 }
 
 #[derive(Debug, Config)]
+#[config(layer_attr(serde(deny_unknown_fields)))]
+pub struct SmarthostConfig {
+    /// SMTP relay host. When set, mail is delivered through this host
+    /// instead of resolving recipient MX records directly.
+    #[config(env = "MAIL_SMARTHOST_HOST")]
+    pub host: Option<String>,
+
+    /// SMTP relay port.
+    #[config(env = "MAIL_SMARTHOST_PORT", default = 587)]
+    pub port: u16,
+
+    /// SMTP authentication username.
+    #[config(env = "MAIL_SMARTHOST_USERNAME")]
+    pub username: Option<String>,
+
+    /// SMTP authentication password.
+    #[config(env = "MAIL_SMARTHOST_PASSWORD")]
+    pub password: Option<String>,
+
+    /// TLS mode. Valid values: "implicit", "starttls", "none". Setting "none"
+    /// alongside a password is rejected at startup to prevent transmitting
+    /// credentials in plaintext.
+    #[config(env = "MAIL_SMARTHOST_TLS", default = "starttls")]
+    pub tls: String,
+
+    /// Max size of the connection pool.
+    #[config(env = "MAIL_SMARTHOST_POOL_SIZE", default = 4)]
+    pub pool_size: u32,
+
+    /// Per-command SMTP timeout in seconds. Bounds the security handshake.
+    #[config(env = "MAIL_SMARTHOST_COMMAND_TIMEOUT_SECS", default = 30)]
+    pub command_timeout_secs: u64,
+
+    /// Total per-message timeout in seconds. Wraps the entire send so a
+    /// stuck relay cannot stall the comms queue.
+    #[config(env = "MAIL_SMARTHOST_TOTAL_TIMEOUT_SECS", default = 60)]
+    pub total_timeout_secs: u64,
+}
+
+#[derive(Debug, Config)]
+#[config(layer_attr(serde(deny_unknown_fields)))]
+pub struct DirectMxConfig {
+    /// Per-command SMTP timeout in seconds.
+    #[config(env = "MAIL_COMMAND_TIMEOUT_SECS", default = 30)]
+    pub command_timeout_secs: u64,
+
+    /// Total per-message timeout across all MX attempts in seconds.
+    #[config(env = "MAIL_TOTAL_TIMEOUT_SECS", default = 60)]
+    pub total_timeout_secs: u64,
+
+    /// Max number of concurrent direct-MX sends. Limits the load placed
+    /// on any single recipient MX during a backlog drain.
+    #[config(env = "MAIL_MAX_CONCURRENT_SENDS", default = 8)]
+    pub max_concurrent_sends: usize,
+
+    /// Require STARTTLS on every MX hop. When false, TLS is
+    /// attempted opportunistically and the session falls back to plaintext
+    /// if the remote does not advertise STARTTLS. Set true to refuse
+    /// plaintext delivery, at the cost of failing sends to MX hosts that
+    /// do not support TLS.
+    #[config(env = "MAIL_REQUIRE_TLS", default = false)]
+    pub require_tls: bool,
+}
+
+#[derive(Debug, Config)]
+#[config(layer_attr(serde(deny_unknown_fields)))]
+pub struct DkimConfig {
+    /// DKIM selector. When unset, outgoing mail is not signed.
+    #[config(env = "MAIL_DKIM_SELECTOR")]
+    pub selector: Option<String>,
+
+    /// DKIM signing domain.
+    #[config(env = "MAIL_DKIM_DOMAIN")]
+    pub domain: Option<String>,
+
+    /// Path to the DKIM private key in PEM format. Supports RSA and
+    /// Ed25519 keys.
+    #[config(env = "MAIL_DKIM_KEY_PATH")]
+    pub private_key_path: Option<String>,
+}
+
+#[derive(Debug, Config)]
+#[config(layer_attr(serde(deny_unknown_fields)))]
 pub struct DiscordConfig {
     /// Discord bot token. When unset, Discord integration is disabled.
     #[config(env = "DISCORD_BOT_TOKEN")]
@@ -770,6 +1121,7 @@ pub struct DiscordConfig {
 }
 
 #[derive(Debug, Config)]
+#[config(layer_attr(serde(deny_unknown_fields)))]
 pub struct TelegramConfig {
     /// Telegram bot token. When unset, Telegram integration is disabled.
     #[config(env = "TELEGRAM_BOT_TOKEN")]
@@ -781,14 +1133,7 @@ pub struct TelegramConfig {
 }
 
 #[derive(Debug, Config)]
-pub struct SignalConfig {
-    /// Protocol state is stored in postgres' signal_* tables.
-    /// Link a device via the admin API before enabling.
-    #[config(env = "SIGNAL_ENABLED", default = false)]
-    pub enabled: bool,
-}
-
-#[derive(Debug, Config)]
+#[config(layer_attr(serde(deny_unknown_fields)))]
 pub struct NotificationConfig {
     /// Polling interval in milliseconds for the comms queue.
     #[config(env = "NOTIFICATION_POLL_INTERVAL_MS", default = 1000)]
@@ -811,6 +1156,7 @@ pub trait SsoProviderIssuerConfig {
 }
 
 #[derive(Debug, Config)]
+#[config(layer_attr(serde(deny_unknown_fields)))]
 pub struct SsoConfig {
     #[config(nested)]
     pub github: SsoGitHubConfig,
@@ -832,6 +1178,7 @@ pub struct SsoConfig {
 }
 
 #[derive(Debug, Config)]
+#[config(layer_attr(serde(deny_unknown_fields)))]
 pub struct SsoGitHubConfig {
     #[config(env = "SSO_GITHUB_ENABLED", default = false)]
     pub enabled: bool,
@@ -865,6 +1212,7 @@ impl SsoProviderConfig for SsoGitHubConfig {
 }
 
 #[derive(Debug, Config)]
+#[config(layer_attr(serde(deny_unknown_fields)))]
 pub struct SsoDiscordConfig {
     #[config(env = "SSO_DISCORD_ENABLED", default = false)]
     pub enabled: bool,
@@ -898,6 +1246,7 @@ impl SsoProviderConfig for SsoDiscordConfig {
 }
 
 #[derive(Debug, Config)]
+#[config(layer_attr(serde(deny_unknown_fields)))]
 pub struct SsoGoogleConfig {
     #[config(env = "SSO_GOOGLE_ENABLED", default = false)]
     pub enabled: bool,
@@ -931,6 +1280,7 @@ impl SsoProviderConfig for SsoGoogleConfig {
 }
 
 #[derive(Debug, Config)]
+#[config(layer_attr(serde(deny_unknown_fields)))]
 pub struct SsoGitLabConfig {
     #[config(env = "SSO_GITLAB_ENABLED", default = false)]
     pub enabled: bool,
@@ -973,6 +1323,7 @@ impl SsoProviderIssuerConfig for SsoGitLabConfig {
 }
 
 #[derive(Debug, Config)]
+#[config(layer_attr(serde(deny_unknown_fields)))]
 pub struct SsoOidcConfig {
     #[config(env = "SSO_OIDC_ENABLED", default = false)]
     pub enabled: bool,
@@ -1015,6 +1366,7 @@ impl SsoProviderIssuerConfig for SsoOidcConfig {
 }
 
 #[derive(Debug, Config)]
+#[config(layer_attr(serde(deny_unknown_fields)))]
 pub struct SsoAppleConfig {
     #[config(env = "SSO_APPLE_ENABLED", default = false)]
     pub enabled: bool,
@@ -1033,6 +1385,7 @@ pub struct SsoAppleConfig {
 }
 
 #[derive(Debug, Config)]
+#[config(layer_attr(serde(deny_unknown_fields)))]
 pub struct ModerationConfig {
     /// External report-handling service URL.
     #[config(env = "REPORT_SERVICE_URL")]
@@ -1044,6 +1397,7 @@ pub struct ModerationConfig {
 }
 
 #[derive(Debug, Config)]
+#[config(layer_attr(serde(deny_unknown_fields)))]
 pub struct ImportConfig {
     /// Whether the PDS accepts repo imports.
     #[config(env = "ACCEPTING_REPO_IMPORTS", default = true)]
@@ -1075,6 +1429,7 @@ fn split_comma_list(value: &str) -> Result<Vec<String>, std::convert::Infallible
 }
 
 #[derive(Debug, Config)]
+#[config(layer_attr(serde(deny_unknown_fields)))]
 pub struct RippleCacheConfig {
     /// Address to bind the Ripple gossip protocol listener.
     #[config(env = "RIPPLE_BIND", default = "0.0.0.0:0")]
@@ -1098,6 +1453,7 @@ pub struct RippleCacheConfig {
 }
 
 #[derive(Debug, Config)]
+#[config(layer_attr(serde(deny_unknown_fields)))]
 pub struct ScheduledConfig {
     /// Interval in seconds between scheduled delete checks.
     #[config(env = "SCHEDULED_DELETE_CHECK_INTERVAL_SECS", default = 3600)]
@@ -1145,6 +1501,7 @@ pub struct ScheduledConfig {
 }
 
 #[derive(Debug, Config)]
+#[config(layer_attr(serde(deny_unknown_fields)))]
 pub struct TranquilStoreConfig {
     /// Directory for tranquil-store data: the metastore, eventlog, and blockstore.
     #[config(
@@ -1199,3 +1556,317 @@ pub struct TranquilStoreConfig {
 pub fn template() -> String {
     confique::toml::template::<TranquilConfig>(confique::toml::FormatOptions::default())
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn seed_required_env() {
+        let required = [
+            ("PDS_HOSTNAME", "test.local"),
+            ("DATABASE_URL", "postgres://localhost/test"),
+            ("TRANQUIL_PDS_ALLOW_INSECURE_SECRETS", "1"),
+            ("INVITE_CODE_REQUIRED", "false"),
+            ("ENABLE_PDS_HOSTED_DID_WEB", "true"),
+            ("TRANQUIL_LEXICON_OFFLINE", "1"),
+        ];
+        required
+            .iter()
+            .filter(|(k, _)| std::env::var_os(k).is_none())
+            .for_each(|(k, v)| unsafe { std::env::set_var(k, v) });
+    }
+
+    #[test]
+    fn load_rejects_unknown_top_level_key() {
+        let dir = std::env::temp_dir().join(format!(
+            "tranquil-config-unknown-toplevel-{}",
+            std::process::id()
+        ));
+        std::fs::create_dir_all(&dir).expect("mkdir tempdir");
+        let path = dir.join("config.toml");
+        std::fs::write(
+            &path,
+            r#"
+[server]
+hostname = "test.local"
+
+[totally_made_up]
+foo = "bar"
+"#,
+        )
+        .expect("write tempfile");
+
+        let result = TranquilConfig::builder().file(&path).load();
+        let _ = std::fs::remove_file(&path);
+        let _ = std::fs::remove_dir(&dir);
+
+        let err = format!("{:#}", result.expect_err("load must reject unknown key"));
+        assert!(
+            err.contains("totally_made_up"),
+            "expected totally_made_up in error, got {err:?}"
+        );
+    }
+
+    #[test]
+    fn load_rejects_unknown_nested_key() {
+        let dir = std::env::temp_dir().join(format!(
+            "tranquil-config-unknown-nested-{}",
+            std::process::id()
+        ));
+        std::fs::create_dir_all(&dir).expect("mkdir tempdir");
+        let path = dir.join("config.toml");
+        std::fs::write(
+            &path,
+            r#"
+[server]
+hostname = "test.local"
+not_a_real_field = "oops"
+"#,
+        )
+        .expect("write tempfile");
+
+        let result = TranquilConfig::builder().file(&path).load();
+        let _ = std::fs::remove_file(&path);
+        let _ = std::fs::remove_dir(&dir);
+
+        let err = format!("{:#}", result.expect_err("load must reject unknown key"));
+        assert!(
+            err.contains("not_a_real_field"),
+            "expected not_a_real_field in error, got {err:?}"
+        );
+    }
+
+    #[test]
+    fn load_accepts_known_keys() {
+        let dir = std::env::temp_dir().join(format!(
+            "tranquil-config-known-keys-{}",
+            std::process::id()
+        ));
+        std::fs::create_dir_all(&dir).expect("mkdir tempdir");
+        let path = dir.join("config.toml");
+        std::fs::write(
+            &path,
+            r#"
+[server]
+hostname = "test.local"
+port = 3000
+
+[database]
+url = "postgres://localhost/test"
+
+[email.smarthost]
+host = "smtp.example"
+port = 587
+"#,
+        )
+        .expect("write tempfile");
+
+        let result = TranquilConfig::builder().file(&path).load();
+        let _ = std::fs::remove_file(&path);
+        let _ = std::fs::remove_dir(&dir);
+
+        result.expect("known keys must load successfully");
+    }
+
+    #[test]
+    fn serial_validate_rejects_legacy_sendmail_path() {
+        seed_required_env();
+        unsafe { std::env::set_var("SENDMAIL_PATH", "/usr/sbin/sendmail") };
+        let config = TranquilConfig::builder()
+            .env()
+            .load()
+            .expect("load fresh config");
+        let result = config.validate(true);
+        unsafe { std::env::remove_var("SENDMAIL_PATH") };
+
+        let err = result.expect_err("validate must reject SENDMAIL_PATH");
+        let mentions_sendmail = err.errors.iter().any(|e| e.contains("SENDMAIL_PATH"));
+        assert!(
+            mentions_sendmail,
+            "errors did not mention SENDMAIL_PATH: {:?}",
+            err.errors
+        );
+    }
+
+    #[test]
+    fn serial_validate_passes_when_no_legacy_env_set() {
+        seed_required_env();
+        unsafe { std::env::remove_var("SENDMAIL_PATH") };
+        let config = TranquilConfig::builder()
+            .env()
+            .load()
+            .expect("load fresh config");
+        let result = config.validate(true);
+        let leaked_legacy = result
+            .as_ref()
+            .err()
+            .map(|e| e.errors.iter().any(|s| s.contains("SENDMAIL_PATH")))
+            .unwrap_or(false);
+        assert!(
+            !leaked_legacy,
+            "validate spuriously flagged SENDMAIL_PATH when unset: {:?}",
+            result
+        );
+    }
+
+    #[test]
+    fn email_address_predicate_accepts_typical_addresses() {
+        assert!(looks_like_email_address("alice@nel.pet"));
+        assert!(looks_like_email_address("a.b+tag@example.co.uk"));
+    }
+
+    #[test]
+    fn email_address_predicate_rejects_malformed() {
+        assert!(!looks_like_email_address(""));
+        assert!(!looks_like_email_address("no-at-sign"));
+        assert!(!looks_like_email_address("@nel.pet"));
+        assert!(!looks_like_email_address("alice@"));
+        assert!(!looks_like_email_address("alice@nel"));
+        assert!(!looks_like_email_address("a@b@c.com"));
+        assert!(!looks_like_email_address("alice @nel.pet"));
+    }
+
+    #[test]
+    fn dkim_selector_predicate_matches_subdomain_syntax() {
+        assert!(is_valid_dkim_selector("default"));
+        assert!(is_valid_dkim_selector("s2024-q1"));
+        assert!(is_valid_dkim_selector("mailo-2024.nel.pet"));
+        assert!(!is_valid_dkim_selector(""));
+        assert!(!is_valid_dkim_selector("a..b"));
+        assert!(!is_valid_dkim_selector("-leading"));
+        assert!(!is_valid_dkim_selector("trailing-"));
+        assert!(!is_valid_dkim_selector("s_under"));
+    }
+
+    #[test]
+    fn email_validate_disabled_when_from_address_unset() {
+        let cfg = email_config_for_test(EmailOverrides::default());
+        let mut errors = Vec::new();
+        cfg.validate("test.local", &mut errors);
+        assert!(errors.is_empty(), "expected no errors, got {errors:?}");
+    }
+
+    #[test]
+    fn email_validate_rejects_bad_from_address() {
+        let cfg = email_config_for_test(EmailOverrides {
+            from_address: Some("not-an-email"),
+            ..Default::default()
+        });
+        let mut errors = Vec::new();
+        cfg.validate("test.local", &mut errors);
+        assert!(
+            errors.iter().any(|e| e.contains("from_address")),
+            "expected from_address error, got {errors:?}"
+        );
+    }
+
+    #[test]
+    fn email_validate_rejects_smarthost_with_bad_credentials() {
+        let cfg = email_config_for_test(EmailOverrides {
+            from_address: Some("alice@nel.pet"),
+            smarthost_host: Some("smtp.nel.pet"),
+            smarthost_username: Some(""),
+            smarthost_password: Some("hunter2"),
+            ..Default::default()
+        });
+        let mut errors = Vec::new();
+        cfg.validate("test.local", &mut errors);
+        assert!(
+            errors.iter().any(|e| e.contains("smarthost.username")),
+            "expected smarthost.username error, got {errors:?}"
+        );
+    }
+
+    #[test]
+    fn email_validate_rejects_bad_dkim_selector() {
+        let cfg = email_config_for_test(EmailOverrides {
+            from_address: Some("alice@nel.pet"),
+            dkim_selector: Some("-bad"),
+            dkim_domain: Some("nel.pet"),
+            dkim_key_path: Some("/etc/dkim.key"),
+            ..Default::default()
+        });
+        let mut errors = Vec::new();
+        cfg.validate("test.local", &mut errors);
+        assert!(
+            errors.iter().any(|e| e.contains("dkim.selector")),
+            "expected dkim.selector error, got {errors:?}"
+        );
+    }
+
+    #[test]
+    fn tls_validate_accepts_both_paths_unset() {
+        let mut errors = Vec::new();
+        TlsConfig {
+            cert_path: None,
+            key_path: None,
+        }
+        .validate(&mut errors);
+        assert!(errors.is_empty(), "expected no errors, got {errors:?}");
+    }
+
+    #[test]
+    fn tls_validate_accepts_both_paths_set() {
+        let mut errors = Vec::new();
+        TlsConfig {
+            cert_path: Some("/etc/tranquil/cert.pem".to_string()),
+            key_path: Some("/etc/tranquil/key.pem".to_string()),
+        }
+        .validate(&mut errors);
+        assert!(errors.is_empty(), "expected no errors, got {errors:?}");
+    }
+
+    #[test]
+    fn tls_validate_rejects_cert_without_key() {
+        let mut errors = Vec::new();
+        TlsConfig {
+            cert_path: Some("/etc/tranquil/cert.pem".to_string()),
+            key_path: None,
+        }
+        .validate(&mut errors);
+        assert!(
+            errors.iter().any(|e| e.contains("server.tls")),
+            "expected server.tls error, got {errors:?}"
+        );
+    }
+
+    #[derive(Default)]
+    struct EmailOverrides {
+        from_address: Option<&'static str>,
+        smarthost_host: Option<&'static str>,
+        smarthost_username: Option<&'static str>,
+        smarthost_password: Option<&'static str>,
+        dkim_selector: Option<&'static str>,
+        dkim_domain: Option<&'static str>,
+        dkim_key_path: Option<&'static str>,
+    }
+
+    fn email_config_for_test(o: EmailOverrides) -> EmailConfig {
+        EmailConfig {
+            from_address: o.from_address.map(str::to_string),
+            from_name: "Tranquil PDS".to_string(),
+            helo_name: None,
+            smarthost: SmarthostConfig {
+                host: o.smarthost_host.map(str::to_string),
+                port: 587,
+                username: o.smarthost_username.map(str::to_string),
+                password: o.smarthost_password.map(str::to_string),
+                tls: "starttls".to_string(),
+                pool_size: 4,
+                command_timeout_secs: 30,
+                total_timeout_secs: 60,
+            },
+            direct_mx: DirectMxConfig {
+                command_timeout_secs: 30,
+                total_timeout_secs: 60,
+                max_concurrent_sends: 8,
+                require_tls: false,
+            },
+            dkim: DkimConfig {
+                selector: o.dkim_selector.map(str::to_string),
+                domain: o.dkim_domain.map(str::to_string),
+                private_key_path: o.dkim_key_path.map(str::to_string),
+            },
+        }
+    }
+}

crates/tranquil-db-traits/src/backlink.rs

@@ -7,7 +7,7 @@ use uuid::Uuid;
 
 use crate::DbError;
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub enum BacklinkPath {
     Subject,
     SubjectUri,

crates/tranquil-db-traits/src/infra.rs

@@ -244,6 +244,8 @@ pub trait InfraRepository: Send + Sync {
 
     async fn mark_comms_failed(&self, id: Uuid, error: &str) -> Result<(), DbError>;
 
+    async fn mark_comms_failed_permanent(&self, id: Uuid, error: &str) -> Result<(), DbError>;
+
     async fn create_invite_code(
         &self,
         code: &str,

crates/tranquil-db-traits/src/user.rs

@@ -44,6 +44,7 @@ pub struct UserRow {
     pub deactivated_at: Option<DateTime<Utc>>,
     pub takedown_ref: Option<String>,
     pub is_admin: bool,
+    pub inbound_migration: bool,
 }
 
 #[derive(Debug, Clone)]
@@ -995,6 +996,7 @@ pub struct CreatePasswordAccountInput {
     pub telegram_username: Option<String>,
     pub signal_username: Option<String>,
     pub deactivated_at: Option<DateTime<Utc>>,
+    pub inbound_migration: bool,
     pub encrypted_key_bytes: Vec<u8>,
     pub encryption_version: i32,
     pub reserved_key_id: Option<Uuid>,

crates/tranquil-db/src/postgres/infra.rs

@@ -65,9 +65,13 @@ impl InfraRepository for PostgresInfraRepository {
                SET status = 'processing', updated_at = NOW()
                WHERE id IN (
                    SELECT id FROM comms_queue
-                   WHERE status = 'pending'
+                   WHERE attempts < max_attempts
                      AND scheduled_for <= $1
-                     AND attempts < max_attempts
+                     AND (
+                         status = 'pending'
+                         OR (status = 'processing'
+                             AND updated_at < $1 - INTERVAL '10 minutes')
+                     )
                    ORDER BY scheduled_for ASC
                    LIMIT $2
                    FOR UPDATE SKIP LOCKED
@@ -127,6 +131,24 @@ impl InfraRepository for PostgresInfraRepository {
         Ok(())
     }
 
+    async fn mark_comms_failed_permanent(&self, id: Uuid, error: &str) -> Result<(), DbError> {
+        sqlx::query!(
+            r#"UPDATE comms_queue
+               SET status = 'failed'::comms_status,
+                   attempts = max_attempts,
+                   last_error = $2,
+                   updated_at = NOW()
+               WHERE id = $1"#,
+            id,
+            error
+        )
+        .execute(&self.pool)
+        .await
+        .map_err(map_sqlx_error)?;
+
+        Ok(())
+    }
+
     async fn create_invite_code(
         &self,
         code: &str,

crates/tranquil-db/src/postgres/oauth.rs

@@ -374,7 +374,7 @@ impl OAuthRepository for PostgresOAuthRepository {
             WHERE id IN (
                 SELECT id FROM oauth_token
                 WHERE did = $1
-                ORDER BY updated_at ASC
+                ORDER BY created_at DESC
                 OFFSET $2
             )
             "#,

crates/tranquil-db/src/postgres/user.rs

@@ -47,7 +47,7 @@ pub(crate) fn map_sqlx_error(e: sqlx::Error) -> DbError {
 impl UserRepository for PostgresUserRepository {
     async fn get_by_did(&self, did: &Did) -> Result<Option<UserRow>, DbError> {
         let row = sqlx::query!(
-            r#"SELECT id, did, handle, email, created_at, deactivated_at, takedown_ref, is_admin
+            r#"SELECT id, did, handle, email, created_at, deactivated_at, takedown_ref, is_admin, inbound_migration
                FROM users WHERE did = $1"#,
             did.as_str()
         )
@@ -64,12 +64,13 @@ impl UserRepository for PostgresUserRepository {
             deactivated_at: r.deactivated_at,
             takedown_ref: r.takedown_ref,
             is_admin: r.is_admin,
+            inbound_migration: r.inbound_migration,
         }))
     }
 
     async fn get_by_handle(&self, handle: &Handle) -> Result<Option<UserRow>, DbError> {
         let row = sqlx::query!(
-            r#"SELECT id, did, handle, email, created_at, deactivated_at, takedown_ref, is_admin
+            r#"SELECT id, did, handle, email, created_at, deactivated_at, takedown_ref, is_admin, inbound_migration
                FROM users WHERE handle = $1"#,
             handle.as_str()
         )
@@ -86,6 +87,7 @@ impl UserRepository for PostgresUserRepository {
             deactivated_at: r.deactivated_at,
             takedown_ref: r.takedown_ref,
             is_admin: r.is_admin,
+            inbound_migration: r.inbound_migration,
         }))
     }
 
@@ -1863,7 +1865,7 @@ impl UserRepository for PostgresUserRepository {
 
     async fn activate_account(&self, did: &Did) -> Result<bool, DbError> {
         let result = sqlx::query!(
-            "UPDATE users SET deactivated_at = NULL WHERE did = $1",
+            "UPDATE users SET deactivated_at = NULL, inbound_migration = FALSE WHERE did = $1",
             did.as_str()
         )
         .execute(&self.pool)
@@ -2426,8 +2428,8 @@ impl UserRepository for PostgresUserRepository {
                 handle, email, did, password_hash,
                 preferred_comms_channel,
                 discord_username, telegram_username, signal_username,
-                is_admin, deactivated_at, email_verified
-            ) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, FALSE) RETURNING id"#,
+                is_admin, deactivated_at, inbound_migration, email_verified
+            ) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, FALSE) RETURNING id"#,
         )
         .bind(input.handle.as_str())
         .bind(&input.email)
@@ -2439,6 +2441,7 @@ impl UserRepository for PostgresUserRepository {
         .bind(&input.signal_username)
         .bind(is_first_user)
         .bind(input.deactivated_at)
+        .bind(input.inbound_migration)
         .fetch_one(&mut *tx)
         .await;
 

crates/tranquil-oauth-server/src/endpoints/authorize/login.rs

@@ -310,6 +310,7 @@ pub async fn authorize_post(
     State(state): State<AppState>,
     _rate_limit: OAuthRateLimited<OAuthAuthorizeLimit>,
     headers: HeaderMap,
+    client_ip: ClientIp,
     Json(form): Json<AuthorizeSubmit>,
 ) -> Response {
     let json_response = wants_json(&headers);
@@ -488,8 +489,7 @@ pub async fn authorize_post(
     if !password_valid {
         return show_login_error("Invalid identifier or password.", json_response);
     }
-    let is_verified = user.channel_verification.has_any_verified();
-    if !is_verified {
+    if tranquil_api::server::verification_blocks_login(&user.channel_verification) {
         let resend_info = tranquil_api::server::auto_resend_verification(&state, &user.did).await;
         let handle = resend_info
             .as_ref()
@@ -617,7 +617,7 @@ pub async fn authorize_post(
             let device_data = DeviceData {
                 session_id: SessionId::generate(),
                 user_agent: extract_user_agent(&headers),
-                ip_address: extract_client_ip(&headers, None),
+                ip_address: client_ip.into_string(),
                 last_seen_at: Utc::now(),
             };
             if state
@@ -854,8 +854,7 @@ pub async fn authorize_select(
             );
         }
     };
-    let is_verified = user.channel_verification.has_any_verified();
-    if !is_verified {
+    if tranquil_api::server::verification_blocks_login(&user.channel_verification) {
         let resend_info = tranquil_api::server::auto_resend_verification(&state, &did).await;
         return (
             StatusCode::FORBIDDEN,

crates/tranquil-oauth-server/src/endpoints/authorize/mod.rs

@@ -23,7 +23,7 @@ use tranquil_pds::rate_limit::{
 };
 use tranquil_pds::state::AppState;
 use tranquil_pds::types::{Did, Handle, PlainPassword};
-use tranquil_pds::util::extract_client_ip;
+use tranquil_pds::util::ClientIp;
 use tranquil_types::{AuthorizationCode, ClientId, DeviceId as DeviceIdType, RequestId};
 use urlencoding::encode as url_encode;
 

crates/tranquil-oauth-server/src/endpoints/authorize/passkey.rs

@@ -289,9 +289,7 @@ async fn passkey_start_named(
             .into_response();
     }
 
-    let is_verified = user.channel_verification.has_any_verified();
-
-    if !is_verified {
+    if tranquil_api::server::verification_blocks_login(&user.channel_verification) {
         let resend_info = tranquil_api::server::auto_resend_verification(&state, &user.did).await;
         return (
             StatusCode::FORBIDDEN,

crates/tranquil-oauth-server/src/endpoints/authorize/registration.rs

@@ -160,8 +160,10 @@ pub async fn register_complete(
             .into_response();
     }
 
-    let is_verified = match state.repos.user.get_session_info_by_did(&did).await {
-        Ok(Some(info)) => info.channel_verification.has_any_verified(),
+    let login_blocked = match state.repos.user.get_session_info_by_did(&did).await {
+        Ok(Some(info)) => {
+            tranquil_api::server::verification_blocks_login(&info.channel_verification)
+        }
         Ok(None) => {
             return (
                 StatusCode::FORBIDDEN,
@@ -189,7 +191,7 @@ pub async fn register_complete(
         }
     };
 
-    if !is_verified {
+    if login_blocked {
         let resend_info = tranquil_api::server::auto_resend_verification(&state, &did).await;
         return (
             StatusCode::FORBIDDEN,
@@ -300,6 +302,7 @@ pub async fn register_complete(
 pub async fn establish_session(
     State(state): State<AppState>,
     headers: HeaderMap,
+    client_ip: ClientIp,
     auth: tranquil_pds::auth::Auth<tranquil_pds::auth::Active>,
 ) -> Response {
     let did = &auth.did;
@@ -317,7 +320,7 @@ pub async fn establish_session(
             let device_data = DeviceData {
                 session_id: SessionId::generate(),
                 user_agent: extract_user_agent(&headers),
-                ip_address: extract_client_ip(&headers, None),
+                ip_address: client_ip.into_string(),
                 last_seen_at: Utc::now(),
             };
 

crates/tranquil-oauth-server/src/endpoints/authorize/two_factor.rs

@@ -75,6 +75,7 @@ pub async fn authorize_2fa_post(
     State(state): State<AppState>,
     _rate_limit: OAuthRateLimited<OAuthAuthorizeLimit>,
     headers: HeaderMap,
+    client_ip: ClientIp,
     Json(form): Json<Authorize2faSubmit>,
 ) -> Response {
     let json_error = |status: StatusCode, error: &str, description: &str| -> Response {
@@ -251,7 +252,7 @@ pub async fn authorize_2fa_post(
                 let device_data = DeviceData {
                     session_id: SessionId::generate(),
                     user_agent: extract_user_agent(&headers),
-                    ip_address: extract_client_ip(&headers, None),
+                    ip_address: client_ip.into_string(),
                     last_seen_at: Utc::now(),
                 };
                 if state

crates/tranquil-oauth-server/src/endpoints/delegation.rs

@@ -12,7 +12,7 @@ use tranquil_pds::oauth::client::{build_client_metadata, delegation_oauth_urls};
 use tranquil_pds::rate_limit::{LoginLimit, OAuthRateLimited, TotpVerifyLimit};
 use tranquil_pds::state::AppState;
 use tranquil_pds::types::PlainPassword;
-use tranquil_pds::util::extract_client_ip;
+use tranquil_pds::util::ClientIp;
 use tranquil_types::did_doc::{extract_handle, extract_pds_endpoint};
 use tranquil_types::{Did, RequestId};
 
@@ -402,6 +402,7 @@ pub struct DelegationTokenAuthSubmit {
 pub async fn delegation_auth_token(
     State(state): State<AppState>,
     headers: HeaderMap,
+    client_ip: ClientIp,
     auth: Auth<Active>,
     Json(form): Json<DelegationTokenAuthSubmit>,
 ) -> Response {
@@ -428,7 +429,7 @@ pub async fn delegation_auth_token(
         return resp;
     }
 
-    let ip = extract_client_ip(&headers, None);
+    let ip = client_ip.into_string();
     let user_agent = tranquil_pds::util::extract_user_agent(&headers);
 
     finalize_delegation_auth(

crates/tranquil-oauth-server/src/sso_endpoints.rs

@@ -402,13 +402,15 @@ async fn handle_sso_login(
         }
     };
 
-    let is_verified = match state
+    let login_blocked = match state
         .repos
         .user
         .get_session_info_by_did(&identity.did)
         .await
     {
-        Ok(Some(info)) => info.channel_verification.has_any_verified(),
+        Ok(Some(info)) => {
+            tranquil_api::server::verification_blocks_login(&info.channel_verification)
+        }
         Ok(None) => {
             tracing::error!("User not found for SSO login: {}", identity.did);
             return redirect_to_error("Account not found");
@@ -419,7 +421,7 @@ async fn handle_sso_login(
         }
     };
 
-    if !is_verified {
+    if login_blocked {
         tracing::warn!(
             did = %identity.did,
             provider = %provider.as_str(),

crates/tranquil-oauth/Cargo.toml

@@ -23,3 +23,6 @@ sha2 = { workspace = true }
 tokio = { workspace = true }
 tracing = { workspace = true }
 uuid = { workspace = true }
+
+[features]
+native-tls-roots = []

crates/tranquil-oauth/src/client.rs

@@ -78,18 +78,21 @@ impl ClientMetadataCache {
         Self {
             cache: Arc::new(RwLock::new(HashMap::new())),
             jwks_cache: Arc::new(RwLock::new(HashMap::new())),
-            http_client: Client::builder()
-                .timeout(std::time::Duration::from_secs(30))
-                .connect_timeout(std::time::Duration::from_secs(10))
-                .pool_max_idle_per_host(10)
-                .pool_idle_timeout(std::time::Duration::from_secs(90))
-                .user_agent(concat!(
-                    "Tranquil-PDS/",
-                    env!("CARGO_PKG_VERSION"),
-                    " (ATProto; +https://tangled.org/tranquil.farm/tranquil-pds)"
-                ))
-                .build()
-                .unwrap_or_else(|_| Client::new()),
+            http_client: {
+                let builder = Client::builder()
+                    .timeout(std::time::Duration::from_secs(30))
+                    .connect_timeout(std::time::Duration::from_secs(10))
+                    .pool_max_idle_per_host(10)
+                    .pool_idle_timeout(std::time::Duration::from_secs(90))
+                    .user_agent(concat!(
+                        "Tranquil-PDS/",
+                        env!("CARGO_PKG_VERSION"),
+                        " (ATProto; +https://tangled.org/tranquil.farm/tranquil-pds)"
+                    ));
+                #[cfg(feature = "native-tls-roots")]
+                let builder = builder.danger_accept_invalid_certs(true);
+                builder.build().unwrap_or_else(|_| Client::new())
+            },
             cache_ttl_secs,
         }
     }

crates/tranquil-pds/Cargo.toml

@@ -55,6 +55,7 @@ metrics-exporter-prometheus = { workspace = true }
 multibase = { workspace = true }
 multihash = { workspace = true }
 p256 = { workspace = true }
+parking_lot = { workspace = true }
 rand = { workspace = true }
 redis = { workspace = true, optional = true }
 regex = { workspace = true }
@@ -90,6 +91,7 @@ s3-storage = ["tranquil-storage/s3", "dep:aws-config", "dep:aws-sdk-s3"]
 s3 = ["s3-storage"]
 valkey = ["tranquil-cache/valkey", "dep:redis"]
 frontend = []
+native-tls-roots = ["tranquil-oauth/native-tls-roots"]
 
 [dev-dependencies]
 ciborium = { workspace = true }

crates/tranquil-pds/src/api/error.rs

@@ -21,6 +21,8 @@ pub enum ApiError {
     InvalidToken(Option<String>),
     ExpiredToken(Option<String>),
     OAuthExpiredToken(Option<String>),
+    UseDpopNonce(String),
+    InvalidDpopProof(String),
     TokenRequired,
     AccountDeactivated,
     AccountTakedown,
@@ -137,6 +139,8 @@ impl ApiError {
             | Self::InvalidToken(_)
             | Self::PasskeyCounterAnomaly
             | Self::OAuthExpiredToken(_)
+            | Self::UseDpopNonce(_)
+            | Self::InvalidDpopProof(_)
             | Self::ReauthRequired { .. } => StatusCode::UNAUTHORIZED,
             Self::InvalidCode(_) => StatusCode::BAD_REQUEST,
             Self::ExpiredToken(_) => StatusCode::BAD_REQUEST,
@@ -236,6 +240,8 @@ impl ApiError {
             Self::AuthenticationFailed(_) => Cow::Borrowed("AuthenticationFailed"),
             Self::InvalidToken(_) => Cow::Borrowed("InvalidToken"),
             Self::ExpiredToken(_) | Self::OAuthExpiredToken(_) => Cow::Borrowed("ExpiredToken"),
+            Self::UseDpopNonce(_) => Cow::Borrowed("use_dpop_nonce"),
+            Self::InvalidDpopProof(_) => Cow::Borrowed("invalid_dpop_proof"),
             Self::TokenRequired => Cow::Borrowed("TokenRequired"),
             Self::AccountDeactivated => Cow::Borrowed("AccountDeactivated"),
             Self::AccountTakedown => Cow::Borrowed("AccountTakedown"),
@@ -335,6 +341,8 @@ impl ApiError {
             Self::ExpiredToken(msg) | Self::OAuthExpiredToken(msg) => {
                 msg.clone().unwrap_or_else(|| "Token has expired".into())
             }
+            Self::UseDpopNonce(_) => "DPoP nonce required".into(),
+            Self::InvalidDpopProof(msg) => msg.clone(),
             Self::RepoNotFound(msg) => msg
                 .clone()
                 .unwrap_or_else(|| "Repository not found".into()),
@@ -560,6 +568,36 @@ impl IntoResponse for ApiError {
                     ),
                 );
             }
+            Self::UseDpopNonce(nonce) => {
+                match HeaderValue::from_str(nonce) {
+                    Ok(val) => {
+                        response
+                            .headers_mut()
+                            .insert(crate::util::HEADER_DPOP_NONCE, val);
+                    }
+                    Err(err) => {
+                        tracing::error!(
+                            ?err,
+                            nonce_len = nonce.len(),
+                            "generated DPoP nonce is not a valid header value"
+                        );
+                    }
+                }
+                response.headers_mut().insert(
+                    http::header::WWW_AUTHENTICATE,
+                    HeaderValue::from_static(
+                        "DPoP error=\"use_dpop_nonce\", error_description=\"Resource server requires nonce in DPoP proof\"",
+                    ),
+                );
+            }
+            Self::InvalidDpopProof(_) => {
+                response.headers_mut().insert(
+                    http::header::WWW_AUTHENTICATE,
+                    HeaderValue::from_static(
+                        "DPoP error=\"invalid_dpop_proof\", error_description=\"Invalid DPoP proof\"",
+                    ),
+                );
+            }
             _ => {}
         }
         response
@@ -596,6 +634,8 @@ impl From<crate::auth::TokenValidationError> for ApiError {
             crate::auth::TokenValidationError::InvalidToken => {
                 Self::AuthenticationFailed(Some("Invalid token format".to_string()))
             }
+            crate::auth::TokenValidationError::UseDpopNonce(nonce) => Self::UseDpopNonce(nonce),
+            crate::auth::TokenValidationError::InvalidDpopProof(msg) => Self::InvalidDpopProof(msg),
         }
     }
 }
@@ -625,10 +665,8 @@ impl From<crate::auth::extractor::AuthError> for ApiError {
             crate::auth::extractor::AuthError::OAuthExpiredToken(msg) => {
                 Self::OAuthExpiredToken(Some(msg))
             }
-            crate::auth::extractor::AuthError::UseDpopNonce(_)
-            | crate::auth::extractor::AuthError::InvalidDpopProof(_) => {
-                Self::AuthenticationFailed(None)
-            }
+            crate::auth::extractor::AuthError::UseDpopNonce(nonce) => Self::UseDpopNonce(nonce),
+            crate::auth::extractor::AuthError::InvalidDpopProof(msg) => Self::InvalidDpopProof(msg),
         }
     }
 }

crates/tranquil-pds/src/auth/account_verified.rs

@@ -21,6 +21,13 @@ pub async fn require_verified_or_delegated<'a>(
     state: &AppState,
     user: &'a AuthenticatedUser,
 ) -> Result<AccountVerified<'a>, ApiError> {
+    if tranquil_config::get()
+        .server
+        .disable_account_verification_gate
+    {
+        return Ok(AccountVerified { user });
+    }
+
     let is_verified = state
         .repos
         .user

crates/tranquil-pds/src/auth/extractor.rs

@@ -2,7 +2,7 @@ use std::marker::PhantomData;
 
 use axum::{
     extract::{FromRequestParts, OptionalFromRequestParts, OriginalUri},
-    http::{StatusCode, header::AUTHORIZATION, request::Parts},
+    http::{header::AUTHORIZATION, request::Parts},
     response::{IntoResponse, Response},
 };
 use tracing::{debug, error, info};
@@ -35,32 +35,7 @@ pub enum AuthError {
 
 impl IntoResponse for AuthError {
     fn into_response(self) -> Response {
-        match self {
-            Self::UseDpopNonce(nonce) => (
-                StatusCode::UNAUTHORIZED,
-                [
-                    ("DPoP-Nonce", nonce.as_str()),
-                    ("WWW-Authenticate", "DPoP error=\"use_dpop_nonce\""),
-                ],
-                axum::Json(serde_json::json!({
-                    "error": "use_dpop_nonce",
-                    "message": "DPoP nonce required"
-                })),
-            )
-                .into_response(),
-            Self::OAuthExpiredToken(msg) => ApiError::OAuthExpiredToken(Some(msg)).into_response(),
-            Self::InvalidDpopProof(msg) => (
-                StatusCode::UNAUTHORIZED,
-                [("WWW-Authenticate", "DPoP error=\"invalid_dpop_proof\"")],
-                axum::Json(serde_json::json!({
-                    "error": "invalid_dpop_proof",
-                    "message": msg
-                })),
-            )
-                .into_response(),
-            Self::InsufficientScope(msg) => ApiError::InsufficientScope(Some(msg)).into_response(),
-            other => ApiError::from(other).into_response(),
-        }
+        ApiError::from(self).into_response()
     }
 }
 

crates/tranquil-pds/src/auth/mod.rs

@@ -106,7 +106,7 @@ struct CachedUserStatus {
     is_admin: bool,
 }
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[derive(Debug, Clone, PartialEq, Eq)]
 pub enum TokenValidationError {
     AccountDeactivated,
     AccountTakedown,
@@ -115,6 +115,8 @@ pub enum TokenValidationError {
     TokenExpired,
     OAuthTokenExpired,
     InvalidToken,
+    UseDpopNonce(String),
+    InvalidDpopProof(String),
 }
 
 impl fmt::Display for TokenValidationError {
@@ -126,6 +128,8 @@ impl fmt::Display for TokenValidationError {
             Self::AuthenticationFailed => write!(f, "AuthenticationFailed"),
             Self::TokenExpired | Self::OAuthTokenExpired => write!(f, "ExpiredToken"),
             Self::InvalidToken => write!(f, "InvalidToken"),
+            Self::UseDpopNonce(_) => write!(f, "use_dpop_nonce"),
+            Self::InvalidDpopProof(_) => write!(f, "invalid_dpop_proof"),
         }
     }
 }
@@ -613,6 +617,12 @@ pub async fn validate_token_with_dpop(
         Err(crate::oauth::OAuthError::ExpiredToken(_)) => {
             Err(TokenValidationError::OAuthTokenExpired)
         }
+        Err(crate::oauth::OAuthError::UseDpopNonce(nonce)) => {
+            Err(TokenValidationError::UseDpopNonce(nonce))
+        }
+        Err(crate::oauth::OAuthError::InvalidDpopProof(msg)) => {
+            Err(TokenValidationError::InvalidDpopProof(msg))
+        }
         Err(_) => Err(TokenValidationError::AuthenticationFailed),
     }
 }

crates/tranquil-pds/src/comms/mod.rs

@@ -4,7 +4,7 @@ pub use tranquil_comms::{
     CommsChannel, CommsSender, CommsStatus, CommsType, DEFAULT_LOCALE, DiscordSender, EmailSender,
     NewComms, NotificationStrings, QueuedComms, SendError, SignalSender, TelegramSender,
     VALID_LOCALES, format_message, get_strings, is_valid_phone_number, is_valid_signal_username,
-    mime_encode_header, sanitize_header_value, validate_locale,
+    validate_locale,
 };
 
 pub use service::{CommsService, repo as comms_repo, resolve_delivery_channel};

crates/tranquil-pds/src/comms/service.rs

@@ -149,13 +149,19 @@ impl CommsService {
                 }
             }
             Err(e) => {
+                let permanent = e.is_permanent();
                 let error_msg = e.to_string();
                 warn!(
                     comms_id = %comms_id,
                     error = %error_msg,
+                    permanent,
                     "Failed to send comms"
                 );
-                if let Err(db_err) = self.mark_failed(comms_id, &error_msg).await {
+                let db_result = match permanent {
+                    true => self.mark_failed_permanent(comms_id, &error_msg).await,
+                    false => self.mark_failed(comms_id, &error_msg).await,
+                };
+                if let Err(db_err) = db_result {
                     error!(
                         comms_id = %comms_id,
                         error = %db_err,
@@ -173,6 +179,14 @@ impl CommsService {
     async fn mark_failed(&self, id: Uuid, error: &str) -> Result<(), tranquil_db_traits::DbError> {
         self.infra_repo.mark_comms_failed(id, error).await
     }
+
+    async fn mark_failed_permanent(
+        &self,
+        id: Uuid,
+        error: &str,
+    ) -> Result<(), tranquil_db_traits::DbError> {
+        self.infra_repo.mark_comms_failed_permanent(id, error).await
+    }
 }
 
 struct ResolvedRecipient {

crates/tranquil-pds/src/rate_limit/extractor.rs

@@ -9,7 +9,7 @@ use axum::{
 use crate::api::error::ApiError;
 use crate::oauth::OAuthError;
 use crate::state::{AppState, RateLimitKind};
-use crate::util::extract_client_ip;
+use crate::util::client_ip_from_parts;
 
 pub trait RateLimitPolicy: Send + Sync + 'static {
     const KIND: RateLimitKind;
@@ -173,7 +173,7 @@ impl<P: RateLimitPolicy, R: RateLimitRejection> FromRequestParts<AppState>
         parts: &mut Parts,
         state: &AppState,
     ) -> Result<Self, Self::Rejection> {
-        let client_ip = extract_client_ip(&parts.headers, None);
+        let client_ip = client_ip_from_parts(parts);
 
         if !state.check_rate_limit(P::KIND, &client_ip).await {
             tracing::warn!(

crates/tranquil-pds/src/repo_ops.rs

@@ -14,7 +14,7 @@ use jacquard_repo::mst::{Mst, VerifiedWriteOp};
 use jacquard_repo::storage::BlockStore;
 use k256::ecdsa::SigningKey;
 use serde_json::{Value, json};
-use std::collections::{BTreeMap, HashSet};
+use std::collections::{BTreeMap, HashMap, HashSet};
 use std::str::FromStr;
 use std::sync::Arc;
 use tokio::sync::OwnedMutexGuard;
@@ -40,6 +40,7 @@ pub enum CommitError {
     MstOperationFailed(String),
     RecordSerializationFailed(String),
     InvalidCid(String),
+    RecordAlreadyExists(String),
 }
 
 impl std::fmt::Display for CommitError {
@@ -65,6 +66,7 @@ impl std::fmt::Display for CommitError {
                 write!(f, "Failed to serialize record: {}", e)
             }
             Self::InvalidCid(e) => write!(f, "Invalid CID: {}", e),
+            Self::RecordAlreadyExists(key) => write!(f, "Record already exists at {}", key),
         }
     }
 }
@@ -79,6 +81,9 @@ impl From<CommitError> for ApiError {
             }
             CommitError::RepoNotFound => ApiError::RepoNotFound(None),
             CommitError::UserNotFound => ApiError::RepoNotFound(Some("User not found".into())),
+            CommitError::RecordAlreadyExists(key) => {
+                ApiError::InvalidRequest(format!("Record already exists at {key}"))
+            }
             other => {
                 error!("Commit failed: {}", other);
                 ApiError::InternalError(Some("Failed to commit changes".into()))
@@ -162,7 +167,6 @@ pub struct FinalizeParams<'a> {
     pub controller_did: Option<&'a Did>,
     pub delegation_detail: Option<serde_json::Value>,
     pub ops: Vec<RecordOp>,
-    pub modified_keys: &'a [String],
     pub blob_cids: &'a [String],
     pub backlinks_to_add: Vec<Backlink>,
     pub backlinks_to_remove: Vec<AtUri>,
@@ -248,18 +252,8 @@ pub async fn finalize_repo_write(
     let mut inverse_trace = new_settled.clone();
     let mut non_invertible: Vec<String> = Vec::new();
     let mut invert_errors: Vec<String> = Vec::new();
-    for op in params.ops.iter() {
-        let (collection, rkey) = match op {
-            RecordOp::Create {
-                collection, rkey, ..
-            }
-            | RecordOp::Update {
-                collection, rkey, ..
-            }
-            | RecordOp::Delete {
-                collection, rkey, ..
-            } => (collection, rkey),
-        };
+    for op in params.ops.iter().rev() {
+        let (collection, rkey) = op.collection_rkey();
         let key = SmolStr::new(format!("{}/{}", collection, rkey));
         let verified = match op {
             RecordOp::Create { cid, .. } => VerifiedWriteOp::Create {
@@ -427,6 +421,22 @@ pub enum RecordOp {
     },
 }
 
+impl RecordOp {
+    pub fn collection_rkey(&self) -> (&Nsid, &Rkey) {
+        match self {
+            Self::Create {
+                collection, rkey, ..
+            }
+            | Self::Update {
+                collection, rkey, ..
+            }
+            | Self::Delete {
+                collection, rkey, ..
+            } => (collection, rkey),
+        }
+    }
+}
+
 pub struct CommitResult {
     pub commit_cid: Cid,
     pub rev: String,
@@ -457,8 +467,6 @@ pub async fn commit_and_log(
         RecordUpsert, RepoEventType,
     };
 
-    let backlinks_to_add = params.backlinks_to_add;
-    let backlinks_to_remove = params.backlinks_to_remove;
     let CommitParams {
         did,
         user_id,
@@ -471,7 +479,8 @@ pub async fn commit_and_log(
         new_tree_cids,
         blobs,
         obsolete_cids,
-        ..
+        backlinks_to_add,
+        backlinks_to_remove,
     } = params;
     debug_assert_eq!(
         current_root_cid.is_some(),
@@ -517,39 +526,63 @@ pub async fn commit_and_log(
 
     let obsolete_bytes: Vec<Vec<u8>> = obsolete_cids.iter().map(|c| c.to_bytes()).collect();
 
-    let (record_upserts, record_deletes): (Vec<RecordUpsert>, Vec<RecordDelete>) = ops.iter().fold(
-        (Vec::new(), Vec::new()),
-        |(mut upserts, mut deletes), op| {
-            match op {
-                RecordOp::Create {
-                    collection,
-                    rkey,
-                    cid,
-                }
-                | RecordOp::Update {
-                    collection,
-                    rkey,
-                    cid,
-                    ..
-                } => {
-                    upserts.push(RecordUpsert {
-                        collection: collection.clone(),
-                        rkey: rkey.clone(),
-                        cid: crate::types::CidLink::from(cid.as_cid()),
-                    });
-                }
-                RecordOp::Delete {
-                    collection, rkey, ..
-                } => {
-                    deletes.push(RecordDelete {
-                        collection: collection.clone(),
-                        rkey: rkey.clone(),
-                    });
-                }
+    let final_ops: HashMap<(&Nsid, &Rkey), &RecordOp> =
+        ops.iter().map(|op| (op.collection_rkey(), op)).collect();
+
+    let final_record_uris: HashSet<AtUri> = final_ops
+        .iter()
+        .filter(|(_, op)| !matches!(op, RecordOp::Delete { .. }))
+        .map(|((c, r), _)| AtUri::from_parts(did, c, r))
+        .collect();
+
+    let record_upserts: Vec<RecordUpsert> = final_ops
+        .values()
+        .filter_map(|op| match op {
+            RecordOp::Create {
+                collection,
+                rkey,
+                cid,
             }
-            (upserts, deletes)
-        },
-    );
+            | RecordOp::Update {
+                collection,
+                rkey,
+                cid,
+                ..
+            } => Some(RecordUpsert {
+                collection: collection.clone(),
+                rkey: rkey.clone(),
+                cid: crate::types::CidLink::from(cid.as_cid()),
+            }),
+            RecordOp::Delete { .. } => None,
+        })
+        .collect();
+
+    let record_deletes: Vec<RecordDelete> = final_ops
+        .values()
+        .filter_map(|op| match op {
+            RecordOp::Delete {
+                collection, rkey, ..
+            } => Some(RecordDelete {
+                collection: collection.clone(),
+                rkey: rkey.clone(),
+            }),
+            _ => None,
+        })
+        .collect();
+
+    let backlinks_to_add: Vec<Backlink> = backlinks_to_add
+        .into_iter()
+        .filter(|b| final_record_uris.contains(&b.uri))
+        .map(|b| ((b.uri.clone(), b.path), b))
+        .collect::<HashMap<_, _>>()
+        .into_values()
+        .collect();
+
+    let backlinks_to_remove: Vec<AtUri> = backlinks_to_remove
+        .into_iter()
+        .collect::<HashSet<_>>()
+        .into_iter()
+        .collect();
 
     let ops_json: Vec<serde_json::Value> = ops
         .iter()
@@ -684,6 +717,16 @@ pub async fn create_record_internal(
         .await
         .map_err(to_commit_err)?;
 
+    let key = format!("{}/{}", collection, rkey);
+    if mst
+        .get(&key)
+        .await
+        .map_err(|e| CommitError::MstOperationFailed(e.to_string()))?
+        .is_some()
+    {
+        return Err(CommitError::RecordAlreadyExists(key));
+    }
+
     let record_ipld = crate::util::json_to_ipld(record);
     let mut record_bytes = Vec::new();
     serde_ipld_dagcbor::to_writer(&mut record_bytes, &record_ipld)
@@ -693,8 +736,6 @@ pub async fn create_record_internal(
         .put(&record_bytes)
         .await
         .map_err(|e| CommitError::BlockStoreFailed(e.to_string()))?;
-
-    let key = format!("{}/{}", collection, rkey);
     let new_mst = mst
         .add(&key, record_cid)
         .await
@@ -705,7 +746,6 @@ pub async fn create_record_internal(
         rkey: rkey.clone(),
         cid: RecordCid::from(record_cid),
     };
-    let modified_keys = [key];
     let blob_cids = extract_blob_cids(record);
     let record_uri = AtUri::from_parts(did.as_str(), collection.as_str(), rkey.as_str());
     let backlinks = extract_backlinks(&record_uri, record);
@@ -720,7 +760,6 @@ pub async fn create_record_internal(
             controller_did: None,
             delegation_detail: None,
             ops: vec![op],
-            modified_keys: &modified_keys,
             blob_cids: &blob_cids,
             backlinks_to_add: backlinks,
             backlinks_to_remove: vec![],

crates/tranquil-pds/src/scheduled.rs

@@ -399,6 +399,10 @@ pub async fn start_scheduled_tasks(
     let mut compaction_ticker = interval(compaction_interval);
     compaction_ticker.set_missed_tick_behavior(tokio::time::MissedTickBehavior::Skip);
 
+    let compaction_blocklist = Arc::new(parking_lot::Mutex::new(CompactionBlocklist::new(
+        Duration::from_secs(300),
+    )));
+
     let mut reachability_ticker = interval(reachability_interval);
     reachability_ticker.set_missed_tick_behavior(tokio::time::MissedTickBehavior::Skip);
 
@@ -464,8 +468,9 @@ pub async fn start_scheduled_tasks(
                     let store = store.clone();
                     let threshold = cfg.scheduled.compaction_liveness_threshold;
                     let grace_ms = cfg.scheduled.compaction_grace_period_ms;
+                    let blocklist = Arc::clone(&compaction_blocklist);
                     if let Err(e) = tokio::task::spawn_blocking(move || {
-                        run_compaction_pass(&store, threshold, grace_ms)
+                        run_compaction_pass(&store, threshold, grace_ms, &blocklist)
                     }).await.unwrap_or_else(|e| Err(anyhow::anyhow!("compaction task panicked: {e}"))) {
                         error!("Compaction error: {e}");
                     }
@@ -485,6 +490,8 @@ pub async fn start_scheduled_tasks(
                                 live_refcounted = result.live_refcounted,
                                 leaked_blocks = result.leaked_blocks,
                                 repaired_blocks = result.repaired_blocks,
+                                phantom_files_purged = result.phantom_files_purged,
+                                phantom_blocks_purged = result.phantom_blocks_purged,
                                 bloom_heap_mb = result.bloom_heap_bytes / (1024 * 1024),
                                 "reachability walk complete"
                             );
@@ -536,11 +543,44 @@ pub async fn start_scheduled_tasks(
     }
 }
 
+pub struct CompactionBlocklist {
+    entries: std::collections::HashMap<tranquil_store::blockstore::DataFileId, std::time::Instant>,
+    cool_off: Duration,
+}
+
+impl CompactionBlocklist {
+    pub fn new(cool_off: Duration) -> Self {
+        Self {
+            entries: std::collections::HashMap::new(),
+            cool_off,
+        }
+    }
+
+    pub fn record_failure(&mut self, file_id: tranquil_store::blockstore::DataFileId) {
+        self.entries.insert(file_id, std::time::Instant::now());
+    }
+
+    pub fn is_blocked(&self, file_id: tranquil_store::blockstore::DataFileId) -> bool {
+        self.entries
+            .get(&file_id)
+            .is_some_and(|recorded| recorded.elapsed() < self.cool_off)
+    }
+
+    pub fn prune_expired(&mut self) {
+        let cool_off = self.cool_off;
+        self.entries
+            .retain(|_, recorded| recorded.elapsed() < cool_off);
+    }
+}
+
 fn run_compaction_pass(
     store: &tranquil_store::blockstore::TranquilBlockStore,
     liveness_threshold: f64,
     grace_period_ms: u64,
+    blocklist: &parking_lot::Mutex<CompactionBlocklist>,
 ) -> anyhow::Result<()> {
+    blocklist.lock().prune_expired();
+
     match store.cleanup_gc_meta() {
         Ok(0) => {}
         Ok(n) => info!(count = n, "cleaned up stale gc_meta entries"),
@@ -553,7 +593,11 @@ fn run_compaction_pass(
 
     let candidate = liveness_map
         .iter()
-        .filter(|(_, info)| info.total_blocks > 0 && info.ratio() < liveness_threshold)
+        .filter(|(fid, info)| {
+            info.total_blocks > 0
+                && info.ratio() < liveness_threshold
+                && !blocklist.lock().is_blocked(**fid)
+        })
         .min_by(|(_, a), (_, b)| {
             a.ratio()
                 .partial_cmp(&b.ratio())
@@ -574,21 +618,35 @@ fn run_compaction_pass(
                 "compacting data file"
             );
             match store.compact_file(file_id, grace_period_ms) {
-                Ok(result) => {
+                Ok(tranquil_store::blockstore::CompactionResult::Compacted(stats)) => {
                     info!(
-                        file_id = %result.file_id,
-                        reclaimed_bytes = result.reclaimed_bytes,
-                        live_blocks = result.live_blocks,
-                        dead_blocks = result.dead_blocks,
+                        file_id = %stats.file_id,
+                        reclaimed_bytes = stats.reclaimed_bytes,
+                        live_blocks = stats.live_blocks,
+                        dead_blocks = stats.dead_blocks,
                         "compaction complete"
                     );
                     Ok(())
                 }
+                Ok(tranquil_store::blockstore::CompactionResult::Purged {
+                    file_id,
+                    phantom_blocks,
+                }) => {
+                    warn!(
+                        file_id = %file_id,
+                        phantom_blocks,
+                        "compaction target missing on disk, purged phantom index entries"
+                    );
+                    Ok(())
+                }
                 Err(tranquil_store::blockstore::CompactionError::ActiveFileCannotBeCompacted) => {
                     debug!(file_id = %file_id, "skipped active file");
                     Ok(())
                 }
-                Err(e) => Err(anyhow::anyhow!("compaction failed: {e}")),
+                Err(e) => {
+                    blocklist.lock().record_failure(file_id);
+                    Err(anyhow::anyhow!("compaction failed: {e}"))
+                }
             }
         }
     }
@@ -693,6 +751,24 @@ pub async fn generate_repo_car(
             .await
             .context("Failed to fetch blocks")?;
 
+        let missing: Vec<Cid> = chunk
+            .iter()
+            .zip(blocks.iter())
+            .filter_map(|(cid, block_opt)| block_opt.is_none().then_some(*cid))
+            .collect();
+        if !missing.is_empty() {
+            anyhow::bail!(
+                "repo CAR is incomplete: {} block(s) referenced by the MST are missing from storage. First 5: {}",
+                missing.len(),
+                missing
+                    .iter()
+                    .take(5)
+                    .map(|c| c.to_string())
+                    .collect::<Vec<_>>()
+                    .join(", ")
+            );
+        }
+
         chunk
             .iter()
             .zip(blocks.iter())
@@ -746,6 +822,8 @@ pub struct ReachabilityResult {
     pub leaked_blocks: u64,
     pub repaired_blocks: u64,
     pub bloom_heap_bytes: usize,
+    pub phantom_files_purged: u64,
+    pub phantom_blocks_purged: u64,
 }
 
 const REPO_PAGE_SIZE: i64 = 500;
@@ -761,6 +839,7 @@ fn walk_repo_dag_sync(
     store: &tranquil_store::blockstore::TranquilBlockStore,
     head_cid: &Cid,
     reachable: &mut std::collections::HashSet<CidBytes>,
+    phantom_files: &mut std::collections::HashSet<tranquil_store::blockstore::DataFileId>,
 ) -> anyhow::Result<()> {
     let mut to_visit = vec![cid_to_bytes(head_cid)?];
 
@@ -769,15 +848,56 @@ fn walk_repo_dag_sync(
             continue;
         }
 
-        let block = match store.get_block_sync(&cid_bytes)? {
-            Some(b) => b,
-            None => {
+        let block = match store.get_block_sync(&cid_bytes) {
+            Ok(Some(b)) => b,
+            Ok(None) => {
                 tracing::warn!(
                     ?cid_bytes,
                     "referenced block missing during reachability walk"
                 );
                 continue;
             }
+            Err(e) => {
+                let Some(entry) = store.block_index().get(&cid_bytes) else {
+                    tracing::warn!(
+                        ?cid_bytes,
+                        error = %e,
+                        "reachability walk: index entry vanished between read attempt and re-check"
+                    );
+                    continue;
+                };
+                let file_path = store.data_file_path(entry.location.file_id);
+                match file_path.try_exists() {
+                    Ok(false) => {
+                        tracing::warn!(
+                            ?cid_bytes,
+                            file_id = %entry.location.file_id,
+                            error = %e,
+                            "indexed block points at missing data file, scheduling phantom purge"
+                        );
+                        phantom_files.insert(entry.location.file_id);
+                        continue;
+                    }
+                    Ok(true) => {
+                        return Err(anyhow::anyhow!(
+                            "reachability walk read error on present data file {}: {e}",
+                            entry.location.file_id
+                        ));
+                    }
+                    Err(probe_err) => {
+                        tracing::warn!(
+                            ?cid_bytes,
+                            file_id = %entry.location.file_id,
+                            existence_probe_error = %probe_err,
+                            "could not probe data file existence after read error"
+                        );
+                        return Err(anyhow::anyhow!(
+                            "reachability walk read error on file {}: {e}",
+                            entry.location.file_id
+                        ));
+                    }
+                }
+            }
         };
 
         if let Ok(commit) = Commit::from_cbor(&block) {
@@ -858,13 +978,15 @@ pub fn run_reachability_walk(
 
     let mut repos_walked: u64 = 0;
     let mut seen_heads: std::collections::HashMap<Did, CidLink> = std::collections::HashMap::new();
+    let mut phantom_files: std::collections::HashSet<tranquil_store::blockstore::DataFileId> =
+        std::collections::HashSet::new();
 
     paginate_repos(&rt, repo_repo, |page| {
         page.iter().try_for_each(|repo| -> anyhow::Result<()> {
             let cid =
                 Cid::from_str(repo.repo_root_cid.as_str()).context("invalid repo_root_cid")?;
             seen_heads.insert(repo.did.clone(), repo.repo_root_cid.clone());
-            walk_repo_dag_sync(store, &cid, &mut visited)?;
+            walk_repo_dag_sync(store, &cid, &mut visited, &mut phantom_files)?;
             repos_walked = repos_walked.saturating_add(1);
             if repos_walked.is_multiple_of(1000) {
                 info!(
@@ -894,7 +1016,7 @@ pub fn run_reachability_walk(
             let cid =
                 Cid::from_str(repo.repo_root_cid.as_str()).context("invalid repo_root_cid")?;
             let mut extra = std::collections::HashSet::new();
-            walk_repo_dag_sync(store, &cid, &mut extra)?;
+            walk_repo_dag_sync(store, &cid, &mut extra, &mut phantom_files)?;
             extra.iter().for_each(|c| reachable.insert(c));
             seen_heads.insert(repo.did.clone(), repo.repo_root_cid.clone());
             stale_repos = stale_repos.saturating_add(1);
@@ -922,7 +1044,7 @@ pub fn run_reachability_walk(
                 let cid =
                     Cid::from_str(repo.repo_root_cid.as_str()).context("invalid repo_root_cid")?;
                 let mut extra = std::collections::HashSet::new();
-                walk_repo_dag_sync(store, &cid, &mut extra)?;
+                walk_repo_dag_sync(store, &cid, &mut extra, &mut phantom_files)?;
                 extra.iter().for_each(|c| reachable.insert(c));
                 quiesced_stale = quiesced_stale.saturating_add(1);
                 Ok(())
@@ -958,6 +1080,19 @@ pub fn run_reachability_walk(
         }
     };
 
+    let phantom_files_purged = u64::try_from(phantom_files.len()).unwrap_or(u64::MAX);
+    let phantom_blocks_purged = phantom_files
+        .iter()
+        .map(|fid| store.block_index().purge_by_file_id(*fid))
+        .sum::<u64>();
+
+    if phantom_files_purged > 0 {
+        warn!(
+            phantom_files_purged,
+            phantom_blocks_purged, "purged phantom index entries from unreadable data files"
+        );
+    }
+
     Ok(ReachabilityResult {
         repos_walked,
         blocks_visited,
@@ -965,5 +1100,7 @@ pub fn run_reachability_walk(
         leaked_blocks,
         repaired_blocks,
         bloom_heap_bytes,
+        phantom_files_purged,
+        phantom_blocks_purged,
     })
 }

crates/tranquil-pds/src/state.rs

@@ -214,10 +214,10 @@ impl AppState {
     pub async fn new(shutdown: CancellationToken) -> Result<Self, Box<dyn Error>> {
         let cfg = tranquil_config::get();
 
-        match cfg.storage.repo_backend() {
+        let mut state = match cfg.storage.repo_backend() {
             tranquil_config::RepoBackend::TranquilStore => {
                 tracing::info!("tranquil-store repo backend active. EXPERIMENTAL!");
-                Ok(Self::from_store(shutdown).await)
+                Self::from_store(shutdown).await
             }
             tranquil_config::RepoBackend::Postgres => {
                 let database_url = &cfg.database.url;
@@ -247,28 +247,21 @@ impl AppState {
                     .await
                     .map_err(|e| format!("Failed to run migrations: {}", e))?;
 
-                let bootstrap_invite_code = match (
-                    cfg.server.invite_code_required,
-                    sqlx::query_scalar!("SELECT COUNT(*) FROM users")
-                        .fetch_one(&db)
-                        .await,
-                ) {
-                    (true, Ok(Some(0))) => {
-                        let code = crate::util::gen_invite_code();
-                        tracing::info!(
-                            "No users exist and invite codes are required. Bootstrap invite code: {}",
-                            code
-                        );
-                        Some(code)
-                    }
-                    _ => None,
-                };
-
-                let mut state = Self::from_db(db, shutdown).await;
-                state.bootstrap_invite_code = bootstrap_invite_code;
-                Ok(state)
+                Self::from_db(db, shutdown).await
             }
+        };
+
+        if cfg.server.invite_code_required && state.repos.user.count_users().await.unwrap_or(1) == 0
+        {
+            let code = crate::util::gen_invite_code();
+            tracing::info!(
+                "No users exist and invite codes are required. Bootstrap invite code: {}",
+                code
+            );
+            state.bootstrap_invite_code = Some(code);
         }
+
+        Ok(state)
     }
 
     pub async fn from_db(db: PgPool, shutdown: CancellationToken) -> Self {
@@ -523,13 +516,16 @@ fn wire_tranquil_store(
     let metastore =
         Metastore::open(&metastore_dir, metastore_config).expect("failed to open metastore");
 
-    let blockstore = TranquilBlockStore::open(BlockStoreConfig {
-        data_dir: blockstore_data_dir,
-        index_dir: blockstore_index_dir,
-        max_file_size: store_cfg.max_blockstore_file_size,
-        group_commit: Default::default(),
-        shard_count: tranquil_store::blockstore::DEFAULT_SHARD_COUNT,
-    })
+    let blockstore = TranquilBlockStore::open_with_retry(
+        BlockStoreConfig {
+            data_dir: blockstore_data_dir,
+            index_dir: blockstore_index_dir,
+            max_file_size: store_cfg.max_blockstore_file_size,
+            group_commit: Default::default(),
+            shard_count: tranquil_store::blockstore::DEFAULT_SHARD_COUNT,
+        },
+        tranquil_store::blockstore::OpenRetryPolicy::default(),
+    )
     .expect("failed to open blockstore");
 
     let event_log = EventLog::open(
@@ -577,6 +573,18 @@ fn wire_tranquil_store(
                     "repaired orphan data files"
                 );
             }
+            if repair.orphan_hints_removed > 0 {
+                tracing::info!(
+                    removed = repair.orphan_hints_removed,
+                    "repaired orphan hint files"
+                );
+            }
+            if repair.phantom_index_entries_purged > 0 {
+                tracing::info!(
+                    purged = repair.phantom_index_entries_purged,
+                    "purged phantom index entries pointing at missing data files"
+                );
+            }
             if repair.had_errors() {
                 tracing::warn!(errors = repair.repair_errors, "some repairs failed");
             }
@@ -595,6 +603,17 @@ fn wire_tranquil_store(
         }
     }
 
+    if std::env::var("TRANQUIL_PURGE_ORPHAN_REPOS").is_ok_and(|v| v == "1") {
+        match metastore
+            .repo_ops()
+            .purge_orphan_repos(metastore.database())
+        {
+            Ok(0) => tracing::info!("orphan repo purge: no orphans found"),
+            Ok(n) => tracing::info!(purged = n, "orphan repo purge: removed orphan repo_meta"),
+            Err(e) => tracing::error!(error = %e, "orphan repo purge failed"),
+        }
+    }
+
     let notifier = bridge.notifier();
     let signal_db = metastore.database().clone();
     let signal_ks = metastore.signal_keyspace();

crates/tranquil-pds/src/util.rs

@@ -7,6 +7,7 @@ use rand::Rng;
 use serde_json::Value as JsonValue;
 use std::collections::BTreeMap;
 use std::net::SocketAddr;
+use std::num::NonZeroUsize;
 use std::str::FromStr;
 use std::sync::OnceLock;
 
@@ -96,22 +97,99 @@ pub fn generate_random_token() -> String {
     URL_SAFE_NO_PAD.encode(bytes)
 }
 
-pub fn extract_client_ip(headers: &HeaderMap, addr: Option<SocketAddr>) -> String {
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub(crate) enum ForwardedTrust {
+    Peer,
+    Proxies(NonZeroUsize),
+}
+
+fn resolve_trust(configured: Option<usize>, terminates_tls: bool) -> ForwardedTrust {
+    let count = configured.unwrap_or(if terminates_tls { 0 } else { 1 });
+    match NonZeroUsize::new(count) {
+        Some(proxies) => ForwardedTrust::Proxies(proxies),
+        None => ForwardedTrust::Peer,
+    }
+}
+
+pub(crate) fn forwarded_trust() -> ForwardedTrust {
+    match tranquil_config::try_get() {
+        Some(cfg) => resolve_trust(
+            cfg.server.trusted_proxy_count,
+            cfg.server.tls.material().is_some(),
+        ),
+        None => ForwardedTrust::Peer,
+    }
+}
+
+fn forwarded_client_ip(headers: &HeaderMap, trusted: NonZeroUsize) -> Option<String> {
     if let Some(forwarded) = headers.get("x-forwarded-for")
         && let Ok(value) = forwarded.to_str()
-        && let Some(first_ip) = value.split(',').next()
     {
-        return first_ip.trim().to_string();
+        let hops: Vec<&str> = value
+            .split(',')
+            .map(str::trim)
+            .filter(|s| !s.is_empty())
+            .collect();
+        if let Some(client) = hops
+            .len()
+            .checked_sub(trusted.get())
+            .and_then(|idx| hops.get(idx))
+        {
+            return Some((*client).to_string());
+        }
     }
-    if let Some(real_ip) = headers.get("x-real-ip")
+    if trusted.get() == 1
+        && let Some(real_ip) = headers.get("x-real-ip")
         && let Ok(value) = real_ip.to_str()
+        && !value.trim().is_empty()
     {
-        return value.trim().to_string();
+        return Some(value.trim().to_string());
+    }
+    None
+}
+
+pub(crate) fn extract_client_ip(
+    headers: &HeaderMap,
+    addr: Option<SocketAddr>,
+    trust: ForwardedTrust,
+) -> String {
+    if let ForwardedTrust::Proxies(trusted) = trust
+        && let Some(client) = forwarded_client_ip(headers, trusted)
+    {
+        return client;
     }
     addr.map(|a| a.ip().to_string())
         .unwrap_or_else(|| "unknown".to_string())
 }
 
+pub(crate) fn client_ip_from_parts(parts: &axum::http::request::Parts) -> String {
+    let addr = parts
+        .extensions
+        .get::<axum::extract::ConnectInfo<SocketAddr>>()
+        .map(|connect_info| connect_info.0);
+    extract_client_ip(&parts.headers, addr, forwarded_trust())
+}
+
+#[derive(Debug, Clone)]
+pub struct ClientIp(String);
+
+impl ClientIp {
+    pub fn into_string(self) -> String {
+        self.0
+    }
+}
+
+impl<S: Send + Sync> axum::extract::FromRequestParts<S> for ClientIp {
+    type Rejection = std::convert::Infallible;
+
+    async fn from_request_parts(
+        parts: &mut axum::http::request::Parts,
+        _state: &S,
+    ) -> Result<Self, Self::Rejection> {
+        Ok(ClientIp(client_ip_from_parts(parts)))
+    }
+}
+
 pub fn set_discord_bot_username(username: String) {
     DISCORD_BOT_USERNAME.set(username).ok();
 }
@@ -227,6 +305,135 @@ pub fn is_self_hosted_did_web_enabled() -> bool {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use axum::extract::{ConnectInfo, FromRequestParts};
+
+    fn proxies(count: usize) -> ForwardedTrust {
+        ForwardedTrust::Proxies(NonZeroUsize::new(count).unwrap())
+    }
+
+    #[test]
+    fn resolve_trust_override_wins_over_tls() {
+        assert_eq!(resolve_trust(Some(1), true), proxies(1));
+        assert_eq!(resolve_trust(Some(3), false), proxies(3));
+        assert_eq!(resolve_trust(Some(0), true), ForwardedTrust::Peer);
+        assert_eq!(resolve_trust(Some(0), false), ForwardedTrust::Peer);
+    }
+
+    #[test]
+    fn resolve_trust_infers_from_tls_when_unset() {
+        assert_eq!(resolve_trust(None, true), ForwardedTrust::Peer);
+        assert_eq!(resolve_trust(None, false), proxies(1));
+    }
+
+    fn parts_with(
+        header: Option<(&str, &str)>,
+        peer: Option<SocketAddr>,
+    ) -> axum::http::request::Parts {
+        let mut builder = axum::http::Request::builder();
+        if let Some((name, value)) = header {
+            builder = builder.header(name, value);
+        }
+        let mut parts = builder.body(()).unwrap().into_parts().0;
+        if let Some(addr) = peer {
+            parts.extensions.insert(ConnectInfo(addr));
+        }
+        parts
+    }
+
+    #[tokio::test]
+    async fn client_ip_falls_back_to_peer_socket() {
+        let peer: SocketAddr = "203.0.113.7:51000".parse().unwrap();
+        let mut parts = parts_with(None, Some(peer));
+        let ip = ClientIp::from_request_parts(&mut parts, &()).await.unwrap();
+        assert_eq!(ip.into_string(), "203.0.113.7");
+    }
+
+    #[tokio::test]
+    async fn client_ip_ignores_forwarded_when_config_absent() {
+        let peer: SocketAddr = "203.0.113.7:51000".parse().unwrap();
+        let mut parts = parts_with(
+            Some(("x-forwarded-for", "198.51.100.4, 10.0.0.1")),
+            Some(peer),
+        );
+        let ip = ClientIp::from_request_parts(&mut parts, &()).await.unwrap();
+        assert_eq!(ip.into_string(), "203.0.113.7");
+    }
+
+    #[tokio::test]
+    async fn client_ip_unknown_without_headers_or_peer() {
+        let mut parts = parts_with(None, None);
+        let ip = ClientIp::from_request_parts(&mut parts, &()).await.unwrap();
+        assert_eq!(ip.into_string(), "unknown");
+    }
+
+    #[tokio::test]
+    async fn client_ip_renders_ipv6_peer_without_brackets() {
+        let peer: SocketAddr = "[2001:db8::beef]:51000".parse().unwrap();
+        let mut parts = parts_with(None, Some(peer));
+        let ip = ClientIp::from_request_parts(&mut parts, &()).await.unwrap();
+        assert_eq!(ip.into_string(), "2001:db8::beef");
+    }
+
+    #[test]
+    fn extract_client_ip_single_proxy_takes_rightmost_forwarded_hop() {
+        let mut headers = HeaderMap::new();
+        headers.insert(
+            "x-forwarded-for",
+            "9.9.9.9, 198.51.100.4, 10.0.0.1".parse().unwrap(),
+        );
+        let peer: SocketAddr = "203.0.113.7:51000".parse().unwrap();
+        assert_eq!(
+            extract_client_ip(&headers, Some(peer), proxies(1)),
+            "10.0.0.1"
+        );
+    }
+
+    #[test]
+    fn extract_client_ip_two_proxies_skips_inner_hop() {
+        let mut headers = HeaderMap::new();
+        headers.insert(
+            "x-forwarded-for",
+            "9.9.9.9, 198.51.100.4, 10.0.0.1".parse().unwrap(),
+        );
+        let peer: SocketAddr = "203.0.113.7:51000".parse().unwrap();
+        assert_eq!(
+            extract_client_ip(&headers, Some(peer), proxies(2)),
+            "198.51.100.4"
+        );
+    }
+
+    #[test]
+    fn extract_client_ip_more_trusted_proxies_than_hops_uses_peer() {
+        let mut headers = HeaderMap::new();
+        headers.insert("x-forwarded-for", "10.0.0.1".parse().unwrap());
+        let peer: SocketAddr = "203.0.113.7:51000".parse().unwrap();
+        assert_eq!(
+            extract_client_ip(&headers, Some(peer), proxies(2)),
+            "203.0.113.7"
+        );
+    }
+
+    #[test]
+    fn extract_client_ip_ignores_forwarded_headers_for_direct_peer() {
+        let mut headers = HeaderMap::new();
+        headers.insert("x-forwarded-for", "9.9.9.9".parse().unwrap());
+        headers.insert("x-real-ip", "9.9.9.9".parse().unwrap());
+        let peer: SocketAddr = "203.0.113.7:51000".parse().unwrap();
+        assert_eq!(
+            extract_client_ip(&headers, Some(peer), ForwardedTrust::Peer),
+            "203.0.113.7"
+        );
+    }
+
+    #[test]
+    fn extract_client_ip_direct_peer_without_socket_is_unknown() {
+        let mut headers = HeaderMap::new();
+        headers.insert("x-forwarded-for", "9.9.9.9".parse().unwrap());
+        assert_eq!(
+            extract_client_ip(&headers, None, ForwardedTrust::Peer),
+            "unknown"
+        );
+    }
 
     #[test]
     fn test_parse_repeated_query_param_repeated() {

crates/tranquil-pds/tests/common/mod.rs

@@ -191,16 +191,12 @@ async fn setup_with_external_infra() -> String {
 async fn setup_with_testcontainers() -> String {
     let temp_dir = std::env::temp_dir().join(format!("tranquil-pds-test-{}", uuid::Uuid::new_v4()));
     let blob_path = temp_dir.join("blobs");
-    let backup_path = temp_dir.join("backups");
     std::fs::create_dir_all(&blob_path).expect("Failed to create blob temp directory");
-    std::fs::create_dir_all(&backup_path).expect("Failed to create backup temp directory");
     TEST_TEMP_DIR.set(temp_dir).ok();
     let plc_url = setup_mock_plc_directory().await;
     unsafe {
         std::env::set_var("BLOB_STORAGE_BACKEND", "filesystem");
         std::env::set_var("BLOB_STORAGE_PATH", blob_path.to_str().unwrap());
-        std::env::set_var("BACKUP_STORAGE_BACKEND", "filesystem");
-        std::env::set_var("BACKUP_STORAGE_PATH", backup_path.to_str().unwrap());
         std::env::set_var("MAX_IMPORT_SIZE", "100000000");
         std::env::set_var("SKIP_IMPORT_VERIFICATION", "true");
         std::env::set_var("PLC_DIRECTORY_URL", &plc_url);
@@ -242,8 +238,6 @@ async fn setup_with_testcontainers() -> String {
     let plc_url = setup_mock_plc_directory().await;
     unsafe {
         std::env::set_var("BLOB_STORAGE_BACKEND", "s3");
-        std::env::set_var("BACKUP_STORAGE_BACKEND", "s3");
-        std::env::set_var("BACKUP_S3_BUCKET", "test-backups");
         std::env::set_var("S3_BUCKET", "test-bucket");
         std::env::set_var("AWS_ACCESS_KEY_ID", "minioadmin");
         std::env::set_var("AWS_SECRET_ACCESS_KEY", "minioadmin");
@@ -333,8 +327,6 @@ unsafe fn configure_external_storage_env() {
         if std::env::var("S3_ENDPOINT").is_ok() {
             let s3_endpoint = std::env::var("S3_ENDPOINT").unwrap();
             std::env::set_var("BLOB_STORAGE_BACKEND", "s3");
-            std::env::set_var("BACKUP_STORAGE_BACKEND", "s3");
-            std::env::set_var("BACKUP_S3_BUCKET", "test-backups");
             std::env::set_var(
                 "S3_BUCKET",
                 std::env::var("S3_BUCKET").unwrap_or_else(|_| "test-bucket".to_string()),
@@ -356,14 +348,10 @@ unsafe fn configure_external_storage_env() {
             let process_dir =
                 std::env::temp_dir().join(format!("tranquil-pds-test-{}", std::process::id()));
             let blob_path = process_dir.join("blobs");
-            let backup_path = process_dir.join("backups");
             std::fs::create_dir_all(&blob_path).expect("Failed to create blob directory");
-            std::fs::create_dir_all(&backup_path).expect("Failed to create backup directory");
             TEST_TEMP_DIR.set(process_dir).ok();
             std::env::set_var("BLOB_STORAGE_BACKEND", "filesystem");
             std::env::set_var("BLOB_STORAGE_PATH", blob_path.to_str().unwrap());
-            std::env::set_var("BACKUP_STORAGE_BACKEND", "filesystem");
-            std::env::set_var("BACKUP_STORAGE_PATH", backup_path.to_str().unwrap());
         }
         std::env::set_var("MAX_IMPORT_SIZE", "100000000");
         std::env::set_var("SKIP_IMPORT_VERIFICATION", "true");
@@ -622,18 +610,14 @@ async fn setup_store_backend() -> String {
     let temp_dir =
         std::env::temp_dir().join(format!("tranquil-pds-store-{}", uuid::Uuid::new_v4()));
     let blob_path = temp_dir.join("blobs");
-    let backup_path = temp_dir.join("backups");
     let store_path = temp_dir.join("store");
     std::fs::create_dir_all(&blob_path).expect("failed to create blob temp directory");
-    std::fs::create_dir_all(&backup_path).expect("failed to create backup temp directory");
     std::fs::create_dir_all(&store_path).expect("failed to create store temp directory");
     TEST_TEMP_DIR.set(temp_dir).ok();
     let plc_url = setup_mock_plc_directory().await;
     unsafe {
         std::env::set_var("BLOB_STORAGE_BACKEND", "filesystem");
         std::env::set_var("BLOB_STORAGE_PATH", blob_path.to_str().unwrap());
-        std::env::set_var("BACKUP_STORAGE_BACKEND", "filesystem");
-        std::env::set_var("BACKUP_STORAGE_PATH", backup_path.to_str().unwrap());
         std::env::set_var("MAX_IMPORT_SIZE", "100000000");
         std::env::set_var("SKIP_IMPORT_VERIFICATION", "true");
         std::env::set_var("PLC_DIRECTORY_URL", &plc_url);
@@ -790,18 +774,14 @@ async fn setup_cluster_store_backend() -> Option<sqlx::PgPool> {
         uuid::Uuid::new_v4()
     ));
     let blob_path = temp_dir.join("blobs");
-    let backup_path = temp_dir.join("backups");
     let store_path = temp_dir.join("store");
     std::fs::create_dir_all(&blob_path).expect("failed to create blob temp directory");
-    std::fs::create_dir_all(&backup_path).expect("failed to create backup temp directory");
     std::fs::create_dir_all(&store_path).expect("failed to create store temp directory");
     TEST_TEMP_DIR.set(temp_dir).ok();
     let plc_url = setup_mock_plc_directory().await;
     unsafe {
         std::env::set_var("BLOB_STORAGE_BACKEND", "filesystem");
         std::env::set_var("BLOB_STORAGE_PATH", blob_path.to_str().unwrap());
-        std::env::set_var("BACKUP_STORAGE_BACKEND", "filesystem");
-        std::env::set_var("BACKUP_STORAGE_PATH", backup_path.to_str().unwrap());
         std::env::set_var("MAX_IMPORT_SIZE", "100000000");
         std::env::set_var("SKIP_IMPORT_VERIFICATION", "true");
         std::env::set_var("PLC_DIRECTORY_URL", &plc_url);
@@ -847,16 +827,12 @@ async fn setup_cluster_testcontainers() -> Option<sqlx::PgPool> {
     let temp_dir =
         std::env::temp_dir().join(format!("tranquil-pds-cluster-{}", uuid::Uuid::new_v4()));
     let blob_path = temp_dir.join("blobs");
-    let backup_path = temp_dir.join("backups");
     std::fs::create_dir_all(&blob_path).expect("Failed to create blob temp directory");
-    std::fs::create_dir_all(&backup_path).expect("Failed to create backup temp directory");
     TEST_TEMP_DIR.set(temp_dir).ok();
     let plc_url = setup_mock_plc_directory().await;
     unsafe {
         std::env::set_var("BLOB_STORAGE_BACKEND", "filesystem");
         std::env::set_var("BLOB_STORAGE_PATH", blob_path.to_str().unwrap());
-        std::env::set_var("BACKUP_STORAGE_BACKEND", "filesystem");
-        std::env::set_var("BACKUP_STORAGE_PATH", backup_path.to_str().unwrap());
         std::env::set_var("MAX_IMPORT_SIZE", "100000000");
         std::env::set_var("SKIP_IMPORT_VERIFICATION", "true");
         std::env::set_var("PLC_DIRECTORY_URL", &plc_url);

crates/tranquil-pds/tests/handle_domains.rs

@@ -8,7 +8,6 @@ const HANDLE_DOMAIN: &str = "handles.test";
 
 fn set_handle_domain() {
     unsafe {
-        std::env::set_var("AVAILABLE_USER_DOMAINS", HANDLE_DOMAIN);
         std::env::set_var("PDS_USER_HANDLE_DOMAINS", HANDLE_DOMAIN);
     }
 }

crates/tranquil-pds/tests/lifecycle_record.rs

@@ -456,7 +456,7 @@ async fn test_apply_writes_batch() {
         "writes": [
             { "$type": "com.atproto.repo.applyWrites#create", "collection": "app.bsky.feed.post", "rkey": "batch-post-1", "value": { "$type": "app.bsky.feed.post", "text": "First batch post", "createdAt": now } },
             { "$type": "com.atproto.repo.applyWrites#create", "collection": "app.bsky.feed.post", "rkey": "batch-post-2", "value": { "$type": "app.bsky.feed.post", "text": "Second batch post", "createdAt": now } },
-            { "$type": "com.atproto.repo.applyWrites#create", "collection": "app.bsky.actor.profile", "rkey": "self", "value": { "$type": "app.bsky.actor.profile", "displayName": "Batch User" } }
+            { "$type": "com.atproto.repo.applyWrites#update", "collection": "app.bsky.actor.profile", "rkey": "self", "value": { "$type": "app.bsky.actor.profile", "displayName": "Batch User" } }
         ]
     });
     let apply_res = client

crates/tranquil-pds/tests/mst_firehose_e2e.rs

@@ -0,0 +1,475 @@
+mod common;
+mod firehose;
+
+use std::collections::BTreeMap;
+use std::io::Cursor;
+use std::str::FromStr;
+use std::sync::Arc;
+use std::time::Duration;
+
+use bytes::Bytes;
+use cid::Cid;
+use common::*;
+use firehose::{FirehoseConsumer, ParsedCommitFrame};
+use iroh_car::CarReader;
+use jacquard_common::smol_str::SmolStr;
+use jacquard_repo::commit::Commit;
+use jacquard_repo::mst::{Mst, VerifiedWriteOp};
+use jacquard_repo::storage::{BlockStore, MemoryBlockStore};
+use reqwest::StatusCode;
+use serde_json::{Value, json};
+use tranquil_scopes::RepoAction;
+
+async fn car_to_blocks(car_bytes: &[u8]) -> BTreeMap<Cid, Bytes> {
+    let mut reader = CarReader::new(Cursor::new(car_bytes))
+        .await
+        .expect("parse CAR header");
+    let mut blocks = BTreeMap::new();
+    while let Ok(Some((cid, data))) = reader.next_block().await {
+        blocks.insert(cid, Bytes::from(data));
+    }
+    blocks
+}
+
+fn op_to_verified(op: &firehose::ParsedRepoOp) -> Result<VerifiedWriteOp, String> {
+    let key = SmolStr::new(&op.path);
+    match op.action {
+        RepoAction::Create => {
+            let cid = op.cid.ok_or("create op missing cid")?;
+            Ok(VerifiedWriteOp::Create { key, cid })
+        }
+        RepoAction::Update => {
+            let cid = op.cid.ok_or("update op missing cid")?;
+            let prev = op.prev.ok_or("update op missing prev")?;
+            Ok(VerifiedWriteOp::Update { key, cid, prev })
+        }
+        RepoAction::Delete => {
+            let prev = op.prev.ok_or("delete op missing prev")?;
+            Ok(VerifiedWriteOp::Delete { key, prev })
+        }
+    }
+}
+
+async fn verify_frame_forward(frame: &ParsedCommitFrame) -> Result<(), String> {
+    let prev_data = frame
+        .prev_data
+        .ok_or_else(|| "frame missing prev_data (v1.1 required)".to_string())?;
+
+    let blocks = car_to_blocks(&frame.blocks).await;
+    let storage = Arc::new(MemoryBlockStore::new_from_blocks(blocks));
+
+    let commit_bytes = storage
+        .get(&frame.commit)
+        .await
+        .map_err(|e| format!("get commit: {e:?}"))?
+        .ok_or_else(|| format!("CAR missing commit {}", frame.commit))?;
+    let commit = Commit::from_cbor(&commit_bytes).map_err(|e| format!("parse commit: {e:?}"))?;
+    let expected = *commit.data();
+
+    let mut mst = Mst::load(storage, prev_data, None);
+    for op in &frame.ops {
+        let path = &op.path;
+        match op.action {
+            RepoAction::Create | RepoAction::Update => {
+                let cid = op.cid.ok_or_else(|| format!("{path}: op missing cid"))?;
+                mst = mst
+                    .add(path, cid)
+                    .await
+                    .map_err(|e| format!("forward {path}: {e:?}"))?;
+            }
+            RepoAction::Delete => {
+                mst = mst
+                    .delete(path)
+                    .await
+                    .map_err(|e| format!("forward delete {path}: {e:?}"))?;
+            }
+        }
+    }
+    let computed = mst.persist().await.map_err(|e| format!("persist: {e:?}"))?;
+    if computed != expected {
+        return Err(format!(
+            "root mismatch expected={expected} computed={computed}"
+        ));
+    }
+    Ok(())
+}
+
+async fn verify_frame_inverse(frame: &ParsedCommitFrame) -> Result<(), String> {
+    let prev_data = frame
+        .prev_data
+        .ok_or_else(|| "frame missing prev_data (v1.1 required)".to_string())?;
+
+    let blocks = car_to_blocks(&frame.blocks).await;
+    let storage = Arc::new(MemoryBlockStore::new_from_blocks(blocks));
+
+    let commit_bytes = storage
+        .get(&frame.commit)
+        .await
+        .map_err(|e| format!("get commit: {e:?}"))?
+        .ok_or_else(|| format!("CAR missing commit {}", frame.commit))?;
+    let commit = Commit::from_cbor(&commit_bytes).map_err(|e| format!("parse commit: {e:?}"))?;
+    let new_data = *commit.data();
+
+    let mut mst = Mst::load(storage, new_data, None);
+    for op in &frame.ops {
+        let verified = op_to_verified(op)?;
+        let inverted = mst
+            .invert_op(verified.clone())
+            .await
+            .map_err(|e| format!("invert {verified:?}: {e:?}"))?;
+        if !inverted {
+            return Err(format!("op not invertible: {verified:?}"));
+        }
+    }
+    let computed_prev = mst
+        .get_pointer()
+        .await
+        .map_err(|e| format!("get_pointer: {e:?}"))?;
+    if computed_prev != prev_data {
+        return Err(format!(
+            "inverse root mismatch expected={prev_data} computed={computed_prev}"
+        ));
+    }
+    Ok(())
+}
+
+async fn create_record(client: &reqwest::Client, token: &str, did: &str, rkey: &str, text: &str) {
+    let now = chrono::Utc::now().to_rfc3339();
+    let res = client
+        .post(format!(
+            "{}/xrpc/com.atproto.repo.createRecord",
+            base_url().await
+        ))
+        .bearer_auth(token)
+        .json(&json!({
+            "repo": did,
+            "collection": "app.bsky.feed.post",
+            "rkey": rkey,
+            "record": {
+                "$type": "app.bsky.feed.post",
+                "text": text,
+                "createdAt": now,
+            }
+        }))
+        .send()
+        .await
+        .expect("createRecord");
+    assert_eq!(res.status(), StatusCode::OK);
+}
+
+async fn put_record(client: &reqwest::Client, token: &str, did: &str, rkey: &str, text: &str) {
+    let now = chrono::Utc::now().to_rfc3339();
+    let res = client
+        .post(format!(
+            "{}/xrpc/com.atproto.repo.putRecord",
+            base_url().await
+        ))
+        .bearer_auth(token)
+        .json(&json!({
+            "repo": did,
+            "collection": "app.bsky.feed.post",
+            "rkey": rkey,
+            "record": {
+                "$type": "app.bsky.feed.post",
+                "text": text,
+                "createdAt": now,
+            }
+        }))
+        .send()
+        .await
+        .expect("putRecord");
+    assert_eq!(res.status(), StatusCode::OK);
+}
+
+async fn delete_record(client: &reqwest::Client, token: &str, did: &str, rkey: &str) {
+    let res = client
+        .post(format!(
+            "{}/xrpc/com.atproto.repo.deleteRecord",
+            base_url().await
+        ))
+        .bearer_auth(token)
+        .json(&json!({
+            "repo": did,
+            "collection": "app.bsky.feed.post",
+            "rkey": rkey,
+        }))
+        .send()
+        .await
+        .expect("deleteRecord");
+    assert_eq!(res.status(), StatusCode::OK);
+}
+
+async fn apply_writes_batch(client: &reqwest::Client, token: &str, did: &str, writes: Vec<Value>) {
+    let res = client
+        .post(format!(
+            "{}/xrpc/com.atproto.repo.applyWrites",
+            base_url().await
+        ))
+        .bearer_auth(token)
+        .json(&json!({ "repo": did, "writes": writes }))
+        .send()
+        .await
+        .expect("applyWrites");
+    assert_eq!(res.status(), StatusCode::OK);
+}
+
+fn rkey_for(i: usize) -> String {
+    format!("3ke2e{:08}", i)
+}
+
+#[tokio::test]
+async fn websocket_firehose_frames_pass_inductive_forward_and_inverse() {
+    let client = client();
+    let (token, did) = create_account_and_login(&client).await;
+
+    let repos = get_test_repos().await;
+    let cursor = repos.repo.get_max_seq().await.unwrap().as_i64();
+    let consumer = FirehoseConsumer::connect_with_cursor(app_port(), cursor).await;
+    tokio::time::sleep(Duration::from_millis(100)).await;
+
+    let now = chrono::Utc::now().to_rfc3339();
+    let seed: Vec<Value> = (0..120)
+        .map(|i| {
+            json!({
+                "$type": "com.atproto.repo.applyWrites#create",
+                "collection": "app.bsky.feed.post",
+                "rkey": rkey_for(i),
+                "value": {
+                    "$type": "app.bsky.feed.post",
+                    "text": format!("e2e {i}"),
+                    "createdAt": now,
+                }
+            })
+        })
+        .collect();
+    for chunk in seed.chunks(40) {
+        apply_writes_batch(&client, &token, &did, chunk.to_vec()).await;
+    }
+    for i in (0..120).step_by(6) {
+        put_record(&client, &token, &did, &rkey_for(i), &format!("upd {i}")).await;
+    }
+    for i in (2..120).step_by(11) {
+        delete_record(&client, &token, &did, &rkey_for(i)).await;
+    }
+    create_record(&client, &token, &did, "3ke2efinal001", "final").await;
+
+    let target_commits = 3 + 20 + 11 + 1;
+    let frames = consumer
+        .wait_for_commits(&did, target_commits, Duration::from_secs(90))
+        .await;
+    assert!(
+        frames.len() >= target_commits,
+        "expected {} commit frames, got {}",
+        target_commits,
+        frames.len()
+    );
+
+    let mut forward_failures = Vec::new();
+    let mut inverse_failures = Vec::new();
+    for frame in &frames {
+        if frame.prev_data.is_none() {
+            continue;
+        }
+        if frame.ops.is_empty() {
+            continue;
+        }
+        if let Err(msg) = verify_frame_forward(frame).await {
+            forward_failures.push(format!("seq={}: {msg}", frame.seq));
+        }
+        if let Err(msg) = verify_frame_inverse(frame).await {
+            inverse_failures.push(format!("seq={}: {msg}", frame.seq));
+        }
+    }
+    assert!(
+        forward_failures.is_empty(),
+        "forward verification failures:\n  - {}",
+        forward_failures.join("\n  - ")
+    );
+    assert!(
+        inverse_failures.is_empty(),
+        "inverse verification failures:\n  - {}",
+        inverse_failures.join("\n  - ")
+    );
+}
+
+#[tokio::test]
+async fn websocket_firehose_car_root_matches_commit_cid() {
+    let client = client();
+    let (token, did) = create_account_and_login(&client).await;
+
+    let repos = get_test_repos().await;
+    let cursor = repos.repo.get_max_seq().await.unwrap().as_i64();
+    let consumer = FirehoseConsumer::connect_with_cursor(app_port(), cursor).await;
+    tokio::time::sleep(Duration::from_millis(100)).await;
+
+    for i in 0..4 {
+        create_record(&client, &token, &did, &rkey_for(i), "ck").await;
+    }
+
+    let frames = consumer
+        .wait_for_commits(&did, 4, Duration::from_secs(10))
+        .await;
+
+    for frame in &frames {
+        let mut reader = CarReader::new(Cursor::new(&frame.blocks))
+            .await
+            .expect("CAR header");
+        let roots = reader.header().roots();
+        assert_eq!(roots.len(), 1, "CAR must have exactly one root");
+        assert_eq!(
+            roots[0], frame.commit,
+            "CAR root must equal frame commit CID"
+        );
+        let mut found = false;
+        while let Ok(Some((cid, _))) = reader.next_block().await {
+            if cid == frame.commit {
+                found = true;
+            }
+        }
+        assert!(found, "CAR body must contain commit block");
+    }
+}
+
+#[tokio::test]
+async fn websocket_firehose_resumption_from_cursor_yields_valid_frames() {
+    let client = client();
+    let (token, did) = create_account_and_login(&client).await;
+    let repos = get_test_repos().await;
+
+    for i in 0..5 {
+        create_record(&client, &token, &did, &rkey_for(i), "pre").await;
+    }
+
+    let resume_cursor = repos.repo.get_max_seq().await.unwrap().as_i64();
+
+    for i in 5..12 {
+        create_record(&client, &token, &did, &rkey_for(i), "post").await;
+    }
+
+    let consumer = FirehoseConsumer::connect_with_cursor(app_port(), resume_cursor).await;
+    let frames = consumer
+        .wait_for_commits(&did, 7, Duration::from_secs(20))
+        .await;
+    assert!(
+        frames.len() >= 7,
+        "expected 7+ frames after cursor resume, got {}",
+        frames.len()
+    );
+
+    for frame in &frames {
+        if frame.prev_data.is_none() || frame.ops.is_empty() {
+            continue;
+        }
+        verify_frame_forward(frame)
+            .await
+            .unwrap_or_else(|e| panic!("resumed frame seq={} invalid: {e}", frame.seq));
+    }
+}
+
+#[tokio::test]
+async fn websocket_firehose_ops_include_prev_field_for_update_delete() {
+    let client = client();
+    let (token, did) = create_account_and_login(&client).await;
+    let repos = get_test_repos().await;
+    let cursor = repos.repo.get_max_seq().await.unwrap().as_i64();
+    let consumer = FirehoseConsumer::connect_with_cursor(app_port(), cursor).await;
+    tokio::time::sleep(Duration::from_millis(100)).await;
+
+    create_record(&client, &token, &did, "3ke2eprev01", "v1").await;
+    put_record(&client, &token, &did, "3ke2eprev01", "v2").await;
+    delete_record(&client, &token, &did, "3ke2eprev01").await;
+
+    let frames = consumer
+        .wait_for_commits(&did, 3, Duration::from_secs(10))
+        .await;
+    assert!(frames.len() >= 3);
+
+    for frame in &frames {
+        for op in &frame.ops {
+            match op.action {
+                RepoAction::Create => {
+                    assert!(op.cid.is_some(), "create must have cid");
+                    assert!(op.prev.is_none(), "create must not have prev");
+                }
+                RepoAction::Update => {
+                    assert!(op.cid.is_some(), "update must have cid");
+                    assert!(
+                        op.prev.is_some(),
+                        "v1.1 update must carry prev CID (seq={})",
+                        frame.seq
+                    );
+                }
+                RepoAction::Delete => {
+                    assert!(op.cid.is_none(), "delete must have null cid");
+                    assert!(
+                        op.prev.is_some(),
+                        "v1.1 delete must carry prev CID (seq={})",
+                        frame.seq
+                    );
+                }
+            }
+        }
+    }
+}
+
+#[tokio::test]
+async fn websocket_firehose_rebuild_new_mst_from_car_matches_commit_data() {
+    let client = client();
+    let (token, did) = create_account_and_login(&client).await;
+    let repos = get_test_repos().await;
+    let cursor = repos.repo.get_max_seq().await.unwrap().as_i64();
+    let consumer = FirehoseConsumer::connect_with_cursor(app_port(), cursor).await;
+    tokio::time::sleep(Duration::from_millis(100)).await;
+
+    let now = chrono::Utc::now().to_rfc3339();
+    let writes: Vec<Value> = (0..30)
+        .map(|i| {
+            json!({
+                "$type": "com.atproto.repo.applyWrites#create",
+                "collection": "app.bsky.feed.post",
+                "rkey": rkey_for(i),
+                "value": {
+                    "$type": "app.bsky.feed.post",
+                    "text": format!("rb {i}"),
+                    "createdAt": now,
+                }
+            })
+        })
+        .collect();
+    apply_writes_batch(&client, &token, &did, writes).await;
+
+    let frames = consumer
+        .wait_for_commits(&did, 1, Duration::from_secs(10))
+        .await;
+    let last = frames.last().expect("frame");
+
+    let blocks = car_to_blocks(&last.blocks).await;
+    let storage = Arc::new(MemoryBlockStore::new_from_blocks(blocks));
+    let commit_bytes = storage
+        .get(&last.commit)
+        .await
+        .unwrap()
+        .expect("commit block");
+    let commit = Commit::from_cbor(&commit_bytes).unwrap();
+
+    let new_root_cid = *commit.data();
+    let mst = Mst::load(storage, new_root_cid, None);
+    let rehydrated_cid = mst.get_pointer().await.expect("rebuild mst");
+    assert_eq!(
+        rehydrated_cid, new_root_cid,
+        "MST loaded from CAR must yield same root as commit.data()"
+    );
+
+    for op in &last.ops {
+        if op.action == RepoAction::Create {
+            let expected_cid = op.cid.unwrap();
+            let got = mst
+                .get(&op.path)
+                .await
+                .expect("mst.get")
+                .unwrap_or_else(|| panic!("key {} missing from rebuilt tree", op.path));
+            assert_eq!(got, expected_cid, "record CID mismatch for {}", op.path);
+            let _ = Cid::from_str(&expected_cid.to_string()).unwrap();
+        }
+    }
+}

crates/tranquil-pds/tests/mst_inductive_firehose.rs

@@ -124,7 +124,7 @@ async fn verify_inductive_inverse(event: &SequencedEvent) -> Result<(Cid, Cid),
     let new_data_cid = new_commit_data_cid(&storage, &commit_cid).await?;
 
     let mut mst = Mst::load(storage.clone(), new_data_cid, None);
-    for op_value in ops_json(event)? {
+    for op_value in ops_json(event)?.iter().rev() {
         let verified = parse_op_to_verified(op_value)?;
         let inverted = mst
             .invert_op(verified.clone())
@@ -546,6 +546,63 @@ async fn inductive_inverse_verifies_every_commit() {
     report_failures(non_genesis.len(), &failures, "any inverse");
 }
 
+#[tokio::test]
+async fn inductive_inverse_handles_same_rkey_in_batch() {
+    let client = client();
+    let (token, did) = create_account_and_login(&client).await;
+
+    let now = chrono::Utc::now().to_rfc3339();
+    let rkey = rkey_for("dup", 0);
+    create_record(&client, &token, &did, COLLECTION, &rkey).await;
+
+    let writes = vec![
+        json!({
+            "$type": "com.atproto.repo.applyWrites#update",
+            "collection": COLLECTION,
+            "rkey": rkey,
+            "value": {
+                "$type": COLLECTION,
+                "text": "v1",
+                "createdAt": now,
+            }
+        }),
+        json!({
+            "$type": "com.atproto.repo.applyWrites#update",
+            "collection": COLLECTION,
+            "rkey": rkey,
+            "value": {
+                "$type": COLLECTION,
+                "text": "v2",
+                "createdAt": now,
+            }
+        }),
+    ];
+    apply_writes_batch(&client, &token, &did, writes).await;
+
+    let our = our_commit_events(&did).await;
+    let dup_event = our
+        .iter()
+        .find(|e| {
+            ops_json(e)
+                .map(|arr| {
+                    arr.iter()
+                        .filter(|op| op["action"].as_str() == Some("update"))
+                        .count()
+                        == 2
+                })
+                .unwrap_or(false)
+        })
+        .expect("commit event with two same-rkey updates");
+
+    let (exp, got) = verify_inductive_inverse(dup_event)
+        .await
+        .expect("inverse verify should succeed for same-rkey batch");
+    assert_eq!(
+        exp, got,
+        "inverse root mismatch for same-rkey batch: exp={exp} got={got}"
+    );
+}
+
 #[tokio::test]
 async fn prev_cid_chain_walks_to_genesis() {
     let client = client();

crates/tranquil-pds/tests/mst_integrity.rs

@@ -0,0 +1,334 @@
+mod common;
+mod firehose;
+mod helpers;
+
+use std::collections::BTreeMap;
+use std::io::Cursor;
+use std::sync::Arc;
+use std::time::Duration;
+
+use bytes::Bytes;
+use cid::Cid;
+use common::*;
+use firehose::FirehoseConsumer;
+use helpers::build_car_with_signature;
+use iroh_car::CarReader;
+use jacquard_repo::commit::Commit;
+use jacquard_repo::mst::Mst;
+use jacquard_repo::storage::{BlockStore, MemoryBlockStore};
+use k256::ecdsa::SigningKey;
+use reqwest::StatusCode;
+use serde_json::{Value, json};
+use tranquil_db_traits::{EventBlocks, RepoEventType, SequenceNumber, SequencedEvent};
+use tranquil_scopes::RepoAction;
+use tranquil_types::Did;
+
+async fn car_to_blocks(car_bytes: &[u8]) -> (Vec<Cid>, BTreeMap<Cid, Bytes>) {
+    let mut reader = CarReader::new(Cursor::new(car_bytes))
+        .await
+        .expect("parse CAR");
+    let roots = reader.header().roots().to_vec();
+    let mut blocks = BTreeMap::new();
+    while let Ok(Some((cid, data))) = reader.next_block().await {
+        blocks.insert(cid, Bytes::from(data));
+    }
+    (roots, blocks)
+}
+
+async fn create_post(client: &reqwest::Client, token: &str, did: &str, rkey: &str, text: &str) {
+    let now = chrono::Utc::now().to_rfc3339();
+    let res = client
+        .post(format!(
+            "{}/xrpc/com.atproto.repo.createRecord",
+            base_url().await
+        ))
+        .bearer_auth(token)
+        .json(&json!({
+            "repo": did,
+            "collection": "app.bsky.feed.post",
+            "rkey": rkey,
+            "record": {
+                "$type": "app.bsky.feed.post",
+                "text": text,
+                "createdAt": now,
+            }
+        }))
+        .send()
+        .await
+        .expect("createRecord");
+    assert_eq!(res.status(), StatusCode::OK);
+}
+
+#[tokio::test]
+async fn getrepo_car_roundtrips_mst_structure_and_records() {
+    let client = client();
+    let (token, did) = create_account_and_login(&client).await;
+
+    let expected_records: Vec<(String, String)> = (0..20)
+        .map(|i| {
+            let rkey = format!("3krtp{:08}", i);
+            let text = format!("roundtrip record {i}");
+            (rkey, text)
+        })
+        .collect();
+    for (rkey, text) in &expected_records {
+        create_post(&client, &token, &did, rkey, text).await;
+    }
+
+    let res = client
+        .get(format!(
+            "{}/xrpc/com.atproto.sync.getRepo",
+            base_url().await
+        ))
+        .query(&[("did", did.as_str())])
+        .send()
+        .await
+        .expect("getRepo");
+    assert_eq!(res.status(), StatusCode::OK);
+    let car_bytes = res.bytes().await.unwrap();
+
+    let (roots, block_map) = car_to_blocks(&car_bytes).await;
+    assert_eq!(roots.len(), 1, "CAR must have exactly one root");
+    let commit_cid = roots[0];
+    let storage = Arc::new(MemoryBlockStore::new_from_blocks(block_map));
+
+    let commit_bytes = storage
+        .get(&commit_cid)
+        .await
+        .unwrap()
+        .expect("CAR contains commit block");
+    let commit = Commit::from_cbor(&commit_bytes).expect("parse commit");
+    let data_cid = *commit.data();
+
+    let mst = Mst::load(storage.clone(), data_cid, None);
+    let loaded_root = mst.get_pointer().await.expect("load root");
+    assert_eq!(loaded_root, data_cid, "loaded MST pointer == commit.data()");
+
+    for (rkey, _) in &expected_records {
+        let path = format!("app.bsky.feed.post/{rkey}");
+        let leaf = mst
+            .get(&path)
+            .await
+            .expect("mst.get")
+            .unwrap_or_else(|| panic!("record {path} missing from exported MST"));
+        let leaf_bytes = storage
+            .get(&leaf)
+            .await
+            .unwrap()
+            .unwrap_or_else(|| panic!("record block {leaf} missing from CAR"));
+        assert!(!leaf_bytes.is_empty(), "record bytes empty");
+    }
+}
+
+#[tokio::test]
+async fn concurrent_swap_commit_writes_serialize() {
+    let client = client();
+    let (token, did) = create_account_and_login(&client).await;
+
+    create_post(&client, &token, &did, "3kswap00000001", "anchor").await;
+
+    let latest_res = client
+        .get(format!(
+            "{}/xrpc/com.atproto.sync.getLatestCommit",
+            base_url().await
+        ))
+        .query(&[("did", did.as_str())])
+        .send()
+        .await
+        .expect("getLatestCommit");
+    assert_eq!(latest_res.status(), StatusCode::OK);
+    let latest: Value = latest_res.json().await.unwrap();
+    let swap_cid = latest["cid"].as_str().unwrap().to_string();
+
+    let now = chrono::Utc::now().to_rfc3339();
+    let payload_a = json!({
+        "repo": did,
+        "collection": "app.bsky.feed.post",
+        "rkey": "3kswap00000002",
+        "record": {
+            "$type": "app.bsky.feed.post",
+            "text": "writer A",
+            "createdAt": now,
+        },
+        "swapCommit": swap_cid,
+    });
+    let payload_b = json!({
+        "repo": did,
+        "collection": "app.bsky.feed.post",
+        "rkey": "3kswap00000003",
+        "record": {
+            "$type": "app.bsky.feed.post",
+            "text": "writer B",
+            "createdAt": now,
+        },
+        "swapCommit": swap_cid,
+    });
+
+    let base = base_url().await;
+    let (res_a, res_b) = tokio::join!(
+        client
+            .post(format!("{base}/xrpc/com.atproto.repo.putRecord"))
+            .bearer_auth(&token)
+            .json(&payload_a)
+            .send(),
+        client
+            .post(format!("{base}/xrpc/com.atproto.repo.putRecord"))
+            .bearer_auth(&token)
+            .json(&payload_b)
+            .send(),
+    );
+    let status_a = res_a.expect("A send").status();
+    let status_b = res_b.expect("B send").status();
+
+    let ok_a = status_a == StatusCode::OK;
+    let ok_b = status_b == StatusCode::OK;
+    assert!(
+        ok_a ^ ok_b,
+        "exactly one swap_commit write must succeed: status_a={status_a}, status_b={status_b}"
+    );
+}
+
+#[tokio::test]
+async fn imported_repo_emits_commit_event_with_valid_car() {
+    let client = client();
+    let (token, did) = create_account_and_login(&client).await;
+
+    let signing_key = SigningKey::random(&mut rand::thread_rng());
+    let (car_bytes, _car_root_cid) = build_car_with_signature(&did, &signing_key);
+
+    let import_res = client
+        .post(format!(
+            "{}/xrpc/com.atproto.repo.importRepo",
+            base_url().await
+        ))
+        .bearer_auth(&token)
+        .header("Content-Type", "application/vnd.ipld.car")
+        .body(car_bytes)
+        .send()
+        .await
+        .expect("importRepo");
+    assert_eq!(
+        import_res.status(),
+        StatusCode::OK,
+        "import failed: {:?}",
+        import_res.text().await.unwrap_or_default()
+    );
+
+    let repos = get_test_repos().await;
+    let typed_did = Did::new(did.clone()).unwrap();
+    let events = repos
+        .repo
+        .get_events_since_seq(SequenceNumber::ZERO, None)
+        .await
+        .expect("events");
+    let our: Vec<&SequencedEvent> = events
+        .iter()
+        .filter(|e| e.did == typed_did && e.event_type == RepoEventType::Commit)
+        .collect();
+    let last = our.last().expect("at least one commit event after import");
+
+    let inline = match last.blocks.as_ref().expect("blocks present") {
+        EventBlocks::Inline(v) => v,
+        _ => panic!("expected inline blocks"),
+    };
+    assert!(
+        !inline.is_empty(),
+        "import event inline blocks must not be empty"
+    );
+
+    let have_commit = inline.iter().any(|b| {
+        let cid = Cid::read_bytes(b.cid_bytes.as_slice()).unwrap();
+        last.commit_cid
+            .as_ref()
+            .and_then(|c| c.to_cid())
+            .map(|commit_cid| cid == commit_cid)
+            .unwrap_or(false)
+    });
+    assert!(have_commit, "import event CAR must include commit block");
+}
+
+#[tokio::test]
+async fn firehose_commit_block_bytes_roundtrip_to_same_cid() {
+    let client = client();
+    let (token, did) = create_account_and_login(&client).await;
+
+    let repos = get_test_repos().await;
+    let cursor = repos.repo.get_max_seq().await.unwrap().as_i64();
+    let consumer = FirehoseConsumer::connect_with_cursor(app_port(), cursor).await;
+    tokio::time::sleep(Duration::from_millis(100)).await;
+
+    create_post(&client, &token, &did, "3krt001", "round-trip me").await;
+    let frames = consumer
+        .wait_for_commits(&did, 1, Duration::from_secs(10))
+        .await;
+    let frame = frames.last().expect("frame");
+
+    let (_, block_map) = car_to_blocks(&frame.blocks).await;
+    use sha2::{Digest, Sha256};
+    for (cid, bytes) in &block_map {
+        let mut hasher = Sha256::new();
+        hasher.update(bytes);
+        let hash = hasher.finalize();
+        let mh = multihash::Multihash::wrap(0x12, hash.as_slice()).expect("wrap");
+        let recomputed = Cid::new_v1(cid.codec(), mh);
+        assert_eq!(
+            recomputed, *cid,
+            "CAR block {cid} bytes do not hash back to same CID"
+        );
+    }
+}
+
+#[tokio::test]
+async fn firehose_commit_car_contains_new_record_bytes_for_every_create() {
+    let client = client();
+    let (token, did) = create_account_and_login(&client).await;
+
+    let repos = get_test_repos().await;
+    let cursor = repos.repo.get_max_seq().await.unwrap().as_i64();
+    let consumer = FirehoseConsumer::connect_with_cursor(app_port(), cursor).await;
+    tokio::time::sleep(Duration::from_millis(100)).await;
+
+    let now = chrono::Utc::now().to_rfc3339();
+    let writes: Vec<Value> = (0..8)
+        .map(|i| {
+            json!({
+                "$type": "com.atproto.repo.applyWrites#create",
+                "collection": "app.bsky.feed.post",
+                "rkey": format!("3krec{:08}", i),
+                "value": {
+                    "$type": "app.bsky.feed.post",
+                    "text": format!("rec {i}"),
+                    "createdAt": now,
+                }
+            })
+        })
+        .collect();
+    let res = client
+        .post(format!(
+            "{}/xrpc/com.atproto.repo.applyWrites",
+            base_url().await
+        ))
+        .bearer_auth(&token)
+        .json(&json!({ "repo": did, "writes": writes }))
+        .send()
+        .await
+        .expect("applyWrites");
+    assert_eq!(res.status(), StatusCode::OK);
+
+    let frames = consumer
+        .wait_for_commits(&did, 1, Duration::from_secs(10))
+        .await;
+    let frame = frames.last().expect("frame");
+
+    let (_, block_map) = car_to_blocks(&frame.blocks).await;
+    for op in &frame.ops {
+        if op.action == RepoAction::Create {
+            let cid = op.cid.expect("create cid");
+            assert!(
+                block_map.contains_key(&cid),
+                "record CID {cid} for path {} missing from CAR",
+                op.path
+            );
+        }
+    }
+}

crates/tranquil-pds/tests/mst_property_fuzz.rs

@@ -0,0 +1,348 @@
+mod common;
+mod mst_verify;
+
+use std::collections::HashMap;
+use std::str::FromStr;
+
+use cid::Cid;
+use common::*;
+use jacquard_common::smol_str::SmolStr;
+use jacquard_repo::commit::Commit;
+use jacquard_repo::mst::{Mst, VerifiedWriteOp};
+use jacquard_repo::storage::BlockStore;
+use mst_verify::{extract_event_blocks, inline_to_store};
+use rand::rngs::StdRng;
+use rand::{Rng, SeedableRng};
+use reqwest::StatusCode;
+use serde_json::{Value, json};
+use tranquil_db_traits::{RepoEventType, SequenceNumber, SequencedEvent};
+use tranquil_types::Did;
+
+const COLLECTIONS: &[&str] = &[
+    "app.bsky.feed.post",
+    "app.bsky.feed.like",
+    "app.bsky.graph.follow",
+    "app.bsky.feed.repost",
+];
+
+#[derive(Copy, Clone, Debug)]
+enum FuzzOp {
+    Create,
+    Update,
+    Delete,
+}
+
+fn pick_op(rng: &mut StdRng, have_keys: bool) -> FuzzOp {
+    match (have_keys, rng.gen_range(0..10)) {
+        (false, _) => FuzzOp::Create,
+        (_, 0..=5) => FuzzOp::Create,
+        (_, 6..=7) => FuzzOp::Update,
+        _ => FuzzOp::Delete,
+    }
+}
+
+fn random_rkey(rng: &mut StdRng) -> String {
+    let tid_char_pool = b"234567abcdefghijklmnopqrstuvwxyz";
+    let mut out = Vec::with_capacity(13);
+    (0..13).for_each(|_| {
+        let c = tid_char_pool[rng.gen_range(0..tid_char_pool.len())];
+        out.push(c);
+    });
+    String::from_utf8(out).unwrap()
+}
+
+fn random_collection(rng: &mut StdRng) -> &'static str {
+    COLLECTIONS[rng.gen_range(0..COLLECTIONS.len())]
+}
+
+fn record_for_collection(col: &str, text: &str, now: &str) -> Value {
+    match col {
+        "app.bsky.feed.post" | "app.bsky.feed.repost" | "app.bsky.feed.like" => json!({
+            "$type": col,
+            "text": text,
+            "createdAt": now,
+        }),
+        _ => json!({
+            "$type": col,
+            "subject": format!("did:plc:synthetic{text}"),
+            "createdAt": now,
+        }),
+    }
+}
+
+async fn verify_commit_forward_and_inverse(event: &SequencedEvent) -> Result<(), String> {
+    let prev_data = event
+        .prev_data_cid
+        .as_ref()
+        .and_then(|c| c.to_cid())
+        .ok_or("no prev_data_cid")?;
+    let commit_cid = event
+        .commit_cid
+        .as_ref()
+        .and_then(|c| c.to_cid())
+        .ok_or("no commit_cid")?;
+    let inline = extract_event_blocks(event)?;
+    let ops = event
+        .ops
+        .as_ref()
+        .and_then(|v| v.as_array())
+        .ok_or("ops not array")?;
+
+    let storage = inline_to_store(inline);
+    let commit_bytes = storage
+        .get(&commit_cid)
+        .await
+        .map_err(|e| format!("get commit: {e:?}"))?
+        .ok_or("missing commit block")?;
+    let commit = Commit::from_cbor(&commit_bytes).map_err(|e| format!("parse commit: {e:?}"))?;
+    let new_data = *commit.data();
+
+    let mut forward = Mst::load(storage.clone(), prev_data, None);
+    for op in ops {
+        let action = op["action"].as_str().ok_or("op.action")?;
+        let path = op["path"].as_str().ok_or("op.path")?;
+        match action {
+            "create" | "update" => {
+                let cid = Cid::from_str(op["cid"].as_str().ok_or("op.cid")?)
+                    .map_err(|e| format!("{e:?}"))?;
+                forward = forward
+                    .add(path, cid)
+                    .await
+                    .map_err(|e| format!("fwd add {path}: {e:?}"))?;
+            }
+            "delete" => {
+                forward = forward
+                    .delete(path)
+                    .await
+                    .map_err(|e| format!("fwd delete {path}: {e:?}"))?;
+            }
+            other => return Err(format!("unknown action {other}")),
+        }
+    }
+    let got = forward
+        .persist()
+        .await
+        .map_err(|e| format!("persist: {e:?}"))?;
+    if got != new_data {
+        return Err(format!("forward root mismatch exp={new_data} got={got}"));
+    }
+
+    let mut inverse = Mst::load(storage, new_data, None);
+    for op in ops {
+        let action = op["action"].as_str().ok_or("op.action")?;
+        let path = op["path"].as_str().ok_or("op.path")?;
+        let key = SmolStr::new(path);
+        let verified = match action {
+            "create" => {
+                let cid = Cid::from_str(op["cid"].as_str().ok_or("op.cid")?)
+                    .map_err(|e| format!("{e:?}"))?;
+                VerifiedWriteOp::Create { key, cid }
+            }
+            "update" => {
+                let cid = Cid::from_str(op["cid"].as_str().ok_or("op.cid")?)
+                    .map_err(|e| format!("{e:?}"))?;
+                let prev = Cid::from_str(op["prev"].as_str().ok_or("op.prev")?)
+                    .map_err(|e| format!("{e:?}"))?;
+                VerifiedWriteOp::Update { key, cid, prev }
+            }
+            "delete" => {
+                let prev = Cid::from_str(op["prev"].as_str().ok_or("op.prev")?)
+                    .map_err(|e| format!("{e:?}"))?;
+                VerifiedWriteOp::Delete { key, prev }
+            }
+            other => return Err(format!("unknown action {other}")),
+        };
+        let inverted = inverse
+            .invert_op(verified.clone())
+            .await
+            .map_err(|e| format!("invert {verified:?}: {e:?}"))?;
+        if !inverted {
+            return Err(format!("op not invertible: {verified:?}"));
+        }
+    }
+    let got_prev = inverse
+        .get_pointer()
+        .await
+        .map_err(|e| format!("get_pointer: {e:?}"))?;
+    if got_prev != prev_data {
+        return Err(format!(
+            "inverse root mismatch exp={prev_data} got={got_prev}"
+        ));
+    }
+    Ok(())
+}
+
+async fn fuzz_run_with_seed(seed: u64, steps: usize) -> Vec<String> {
+    let client = client();
+    let (token, did) = create_account_and_login(&client).await;
+    let mut rng = StdRng::seed_from_u64(seed);
+
+    let mut live_keys: HashMap<String, String> = HashMap::new();
+
+    for step in 0..steps {
+        let now = chrono::Utc::now().to_rfc3339();
+        let op = pick_op(&mut rng, !live_keys.is_empty());
+        match op {
+            FuzzOp::Create => {
+                let col = random_collection(&mut rng);
+                let rkey = random_rkey(&mut rng);
+                let path = format!("{col}/{rkey}");
+                if live_keys.contains_key(&path) {
+                    continue;
+                }
+                let record = record_for_collection(col, &format!("s{seed}-n{step}"), &now);
+                let res = client
+                    .post(format!(
+                        "{}/xrpc/com.atproto.repo.createRecord",
+                        base_url().await
+                    ))
+                    .bearer_auth(&token)
+                    .json(&json!({
+                        "repo": did,
+                        "collection": col,
+                        "rkey": rkey,
+                        "record": record,
+                    }))
+                    .send()
+                    .await
+                    .expect("createRecord");
+                if res.status() == StatusCode::OK {
+                    live_keys.insert(path, col.to_string());
+                }
+            }
+            FuzzOp::Update => {
+                let keys: Vec<&String> = live_keys.keys().collect();
+                if keys.is_empty() {
+                    continue;
+                }
+                let path = keys[rng.gen_range(0..keys.len())].clone();
+                let col = live_keys.get(&path).unwrap().clone();
+                let rkey = path.split('/').nth(1).unwrap().to_string();
+                let record = record_for_collection(&col, &format!("s{seed}-u{step}"), &now);
+                let res = client
+                    .post(format!(
+                        "{}/xrpc/com.atproto.repo.putRecord",
+                        base_url().await
+                    ))
+                    .bearer_auth(&token)
+                    .json(&json!({
+                        "repo": did,
+                        "collection": col,
+                        "rkey": rkey,
+                        "record": record,
+                    }))
+                    .send()
+                    .await
+                    .expect("putRecord");
+                assert_eq!(res.status(), StatusCode::OK, "putRecord failed");
+            }
+            FuzzOp::Delete => {
+                let keys: Vec<String> = live_keys.keys().cloned().collect();
+                if keys.is_empty() {
+                    continue;
+                }
+                let path = keys[rng.gen_range(0..keys.len())].clone();
+                let col = live_keys.get(&path).unwrap().clone();
+                let rkey = path.split('/').nth(1).unwrap().to_string();
+                let res = client
+                    .post(format!(
+                        "{}/xrpc/com.atproto.repo.deleteRecord",
+                        base_url().await
+                    ))
+                    .bearer_auth(&token)
+                    .json(&json!({
+                        "repo": did,
+                        "collection": col,
+                        "rkey": rkey,
+                    }))
+                    .send()
+                    .await
+                    .expect("deleteRecord");
+                if res.status() == StatusCode::OK {
+                    live_keys.remove(&path);
+                }
+            }
+        }
+    }
+
+    let repos = get_test_repos().await;
+    let typed_did = Did::new(did.clone()).unwrap();
+    let events = repos
+        .repo
+        .get_events_since_seq(SequenceNumber::ZERO, None)
+        .await
+        .expect("get_events_since_seq");
+
+    let our: Vec<SequencedEvent> = events
+        .into_iter()
+        .filter(|e| {
+            e.did == typed_did
+                && e.event_type == RepoEventType::Commit
+                && e.prev_data_cid.is_some()
+                && e.ops
+                    .as_ref()
+                    .and_then(|v| v.as_array())
+                    .is_some_and(|a| !a.is_empty())
+        })
+        .collect();
+
+    let mut failures = Vec::new();
+    for event in &our {
+        if let Err(msg) = verify_commit_forward_and_inverse(event).await {
+            failures.push(format!(
+                "seed={seed} seq={} ops={:?}: {msg}",
+                event.seq.as_i64(),
+                event
+                    .ops
+                    .as_ref()
+                    .and_then(|v| v.as_array())
+                    .map(|a| a.len())
+            ));
+        }
+    }
+    failures
+}
+
+#[tokio::test]
+async fn mst_property_fuzz_seed_1() {
+    let failures = fuzz_run_with_seed(1, 150).await;
+    assert!(
+        failures.is_empty(),
+        "fuzz seed=1 found {} invalid commits:\n  - {}",
+        failures.len(),
+        failures.join("\n  - ")
+    );
+}
+
+#[tokio::test]
+async fn mst_property_fuzz_seed_42() {
+    let failures = fuzz_run_with_seed(42, 150).await;
+    assert!(
+        failures.is_empty(),
+        "fuzz seed=42 found {} invalid commits:\n  - {}",
+        failures.len(),
+        failures.join("\n  - ")
+    );
+}
+
+#[tokio::test]
+async fn mst_property_fuzz_seed_9001() {
+    let failures = fuzz_run_with_seed(9001, 150).await;
+    assert!(
+        failures.is_empty(),
+        "fuzz seed=9001 found {} invalid commits:\n  - {}",
+        failures.len(),
+        failures.join("\n  - ")
+    );
+}
+
+#[tokio::test]
+async fn mst_property_fuzz_deep_tree_seed_7() {
+    let failures = fuzz_run_with_seed(7, 400).await;
+    assert!(
+        failures.is_empty(),
+        "fuzz deep seed=7 found {} invalid commits:\n  - {}",
+        failures.len(),
+        failures.join("\n  - ")
+    );
+}

crates/tranquil-pds/tests/oauth_token_eviction.rs

@@ -0,0 +1,167 @@
+mod common;
+mod helpers;
+
+use chrono::{DateTime, Duration, Utc};
+use common::{base_url, client, get_test_repos};
+use futures::StreamExt;
+use helpers::verify_new_account;
+use reqwest::StatusCode;
+use serde_json::{Value, json};
+use tranquil_oauth::{
+    AuthorizationRequestParameters, ClientAuth, CodeChallengeMethod, ResponseType, TokenData,
+    TokenId,
+};
+use tranquil_types::Did;
+
+async fn create_account_and_get_did(handle: &str, email: &str, password: &str) -> Did {
+    let client = client();
+    let res = client
+        .post(format!(
+            "{}/xrpc/com.atproto.server.createAccount",
+            base_url().await
+        ))
+        .json(&json!({
+            "handle": handle,
+            "email": email,
+            "password": password,
+        }))
+        .send()
+        .await
+        .expect("createAccount request failed");
+    assert_eq!(res.status(), StatusCode::OK, "createAccount failed");
+    let body: Value = res.json().await.expect("invalid createAccount JSON");
+    let did_str = body["did"]
+        .as_str()
+        .expect("no did in response")
+        .to_string();
+    let _ = verify_new_account(&client, &did_str).await;
+    Did::new(did_str).expect("invalid DID format")
+}
+
+fn make_token_data(did: &Did, token_id: &str, created_at: DateTime<Utc>) -> TokenData {
+    let client_id = "https://squid.nel.pet/client".to_string();
+    TokenData {
+        did: did.clone(),
+        token_id: TokenId(token_id.to_string()),
+        created_at,
+        updated_at: created_at,
+        expires_at: created_at + Duration::hours(1),
+        client_id: client_id.clone(),
+        client_auth: ClientAuth::None,
+        device_id: None,
+        parameters: AuthorizationRequestParameters {
+            response_type: ResponseType::Code,
+            client_id,
+            redirect_uri: "https://squid.nel.pet/cb".to_string(),
+            scope: None,
+            state: None,
+            code_challenge: "x".to_string(),
+            code_challenge_method: CodeChallengeMethod::S256,
+            response_mode: None,
+            login_hint: None,
+            dpop_jkt: None,
+            prompt: None,
+            extra: None,
+        },
+        details: None,
+        code: None,
+        current_refresh_token: None,
+        scope: None,
+        controller_did: None,
+    }
+}
+
+async fn seed_tokens(repos: &tranquil_db::PostgresRepositories, tokens: &[TokenData]) {
+    futures::stream::iter(tokens)
+        .for_each(|token| async move {
+            repos
+                .oauth
+                .create_token(token)
+                .await
+                .expect("token insert failed");
+        })
+        .await;
+}
+
+#[tokio::test]
+async fn delete_oldest_tokens_evicts_lowest_created_at() {
+    let ts = Utc::now().timestamp_millis();
+    let handle = format!("tok-evict-{}.test", ts);
+    let email = format!("tok-evict-{}@test.com", ts);
+    let did = create_account_and_get_did(&handle, &email, "EvictTest123!").await;
+
+    let repos = get_test_repos().await;
+
+    let base = Utc::now();
+    let token_ids: Vec<String> = (0..5).map(|i| format!("tok-{}-{}", ts, i)).collect();
+    let tokens: Vec<TokenData> = (0i64..)
+        .zip(token_ids.iter())
+        .map(|(offset, tid)| make_token_data(&did, tid, base + Duration::seconds(offset)))
+        .collect();
+    seed_tokens(repos, &tokens).await;
+
+    let count_before = repos
+        .oauth
+        .count_tokens_for_user(&did)
+        .await
+        .expect("count failed");
+    assert_eq!(count_before, 5, "all 5 tokens should be present");
+
+    let deleted = repos
+        .oauth
+        .delete_oldest_tokens_for_user(&did, 3)
+        .await
+        .expect("delete failed");
+    assert_eq!(deleted, 2, "two oldest tokens should be deleted");
+
+    let remaining = repos
+        .oauth
+        .list_tokens_for_user(&did)
+        .await
+        .expect("list failed");
+    assert_eq!(remaining.len(), 3, "three newest tokens should remain");
+
+    let remaining_ids: std::collections::HashSet<String> =
+        remaining.iter().map(|t| t.token_id.0.clone()).collect();
+    let expected_ids: std::collections::HashSet<String> = token_ids[2..].iter().cloned().collect();
+    assert_eq!(
+        remaining_ids, expected_ids,
+        "surviving tokens must be the three newest by created_at"
+    );
+}
+
+#[tokio::test]
+async fn delete_oldest_tokens_no_op_when_under_keep_count() {
+    let ts = Utc::now().timestamp_millis();
+    let handle = format!("tok-evict-noop-{}.test", ts);
+    let email = format!("tok-evict-noop-{}@test.com", ts);
+    let did = create_account_and_get_did(&handle, &email, "EvictTest123!").await;
+
+    let repos = get_test_repos().await;
+
+    let base = Utc::now();
+    let tokens: Vec<TokenData> = (0i64..2)
+        .map(|offset| {
+            make_token_data(
+                &did,
+                &format!("noop-tok-{}-{}", ts, offset),
+                base + Duration::seconds(offset),
+            )
+        })
+        .collect();
+    seed_tokens(repos, &tokens).await;
+
+    let deleted = repos
+        .oauth
+        .delete_oldest_tokens_for_user(&did, 5)
+        .await
+        .expect("delete failed");
+    assert_eq!(deleted, 0, "nothing to delete when count <= keep");
+
+    let remaining = repos
+        .oauth
+        .list_tokens_for_user(&did)
+        .await
+        .expect("list failed");
+    assert_eq!(remaining.len(), 2);
+}

crates/tranquil-pds/tests/security_fixes.rs

@@ -1,43 +1,7 @@
 mod common;
-use tranquil_pds::comms::{
-    SendError, is_valid_phone_number, is_valid_signal_username, sanitize_header_value,
-};
+use tranquil_pds::comms::{SendError, is_valid_phone_number, is_valid_signal_username};
 use tranquil_pds::image::{ImageError, ImageProcessor};
 
-#[test]
-fn test_header_injection_sanitization() {
-    let malicious = "Injected\r\nBcc: attacker@evil.com";
-    let sanitized = sanitize_header_value(malicious);
-    assert!(!sanitized.contains('\r') && !sanitized.contains('\n'));
-    assert!(sanitized.contains("Injected") && sanitized.contains("Bcc:"));
-
-    let normal = "Normal Subject Line";
-    assert_eq!(sanitize_header_value(normal), "Normal Subject Line");
-
-    let padded = "  Subject  ";
-    assert_eq!(sanitize_header_value(padded), "Subject");
-
-    let multi_newline = "Line1\r\nLine2\nLine3\rLine4";
-    let sanitized = sanitize_header_value(multi_newline);
-    assert!(!sanitized.contains('\r') && !sanitized.contains('\n'));
-    assert!(sanitized.contains("Line1") && sanitized.contains("Line4"));
-
-    let header_injection = "Normal Subject\r\nBcc: attacker@evil.com\r\nX-Injected: value";
-    let sanitized = sanitize_header_value(header_injection);
-    assert_eq!(sanitized.split("\r\n").count(), 1);
-    assert!(
-        sanitized.contains("Normal Subject")
-            && sanitized.contains("Bcc:")
-            && sanitized.contains("X-Injected:")
-    );
-
-    let with_null = "client\0id";
-    assert!(sanitize_header_value(with_null).contains("client"));
-
-    let long_input = "x".repeat(10000);
-    assert!(!sanitize_header_value(&long_input).is_empty());
-}
-
 #[test]
 fn test_phone_number_validation() {
     assert!(is_valid_phone_number("+1234567890"));

crates/tranquil-pds/tests/store_parity.rs

@@ -150,6 +150,7 @@ async fn seed_user(repos: &PostgresRepositories, did: &Did, handle: &Handle) ->
         telegram_username: None,
         signal_username: None,
         deactivated_at: None,
+        inbound_migration: false,
         encrypted_key_bytes: vec![0u8; 32],
         encryption_version: 0,
         reserved_key_id: None,
@@ -1465,6 +1466,37 @@ async fn parity_delete_all_records() {
     assert_eq!(store_colls.len(), 0);
 }
 
+#[tokio::test]
+async fn parity_account_deletion_clears_records_on_reregister() {
+    let f = ParityFixture::new().await;
+    let did = test_did("cuttle");
+    let handle = test_handle("cuttle");
+    let collection = test_nsid("post");
+
+    let (pg_uid, store_uid) = seed_repos(&f, &did, &handle).await;
+
+    let records: Vec<(Rkey, CidLink)> = (0u8..3)
+        .map(|i| (test_rkey(&format!("3l{:02}aaaaaaaaa", i)), test_cid(i + 1)))
+        .collect();
+    seed_records(&f.pg, pg_uid, &collection, &records).await;
+    seed_records(&f.store, store_uid, &collection, &records).await;
+
+    f.pg.user
+        .delete_account_complete(pg_uid, &did)
+        .await
+        .unwrap();
+    f.store
+        .user
+        .delete_account_complete(store_uid, &did)
+        .await
+        .unwrap();
+
+    let (pg_uid2, store_uid2) = seed_repos(&f, &did, &handle).await;
+
+    assert_eq!(f.pg.repo.count_records(pg_uid2).await.unwrap(), 0);
+    assert_eq!(f.store.repo.count_records(store_uid2).await.unwrap(), 0);
+}
+
 #[tokio::test]
 async fn parity_plc_tokens() {
     let f = ParityFixture::new().await;

crates/tranquil-server/Cargo.toml

@@ -12,13 +12,22 @@ tranquil-oauth-server = { workspace = true }
 tranquil-config = { workspace = true }
 tranquil-signal = { workspace = true }
 
+arc-swap = { workspace = true }
 axum = { workspace = true }
 clap = { workspace = true }
 dotenvy = { workspace = true }
 ed25519-dalek = { workspace = true }
+futures-util = { workspace = true }
 hex = { workspace = true }
+hyper = { workspace = true }
+hyper-util = { workspace = true }
+rustls = { workspace = true }
+rustls-pemfile = { workspace = true }
+thiserror = { workspace = true }
 tokio = { workspace = true }
+tokio-rustls = { workspace = true }
 tokio-util = { workspace = true }
+tower = { workspace = true }
 tracing = { workspace = true }
 tracing-subscriber = { workspace = true }
 
@@ -27,3 +36,4 @@ default = ["frontend", "s3", "valkey"]
 frontend = ["tranquil-pds/frontend"]
 s3 = ["tranquil-pds/s3"]
 valkey = ["tranquil-pds/valkey"]
+native-tls-roots = ["tranquil-pds/native-tls-roots"]

crates/tranquil-server/src/main.rs

@@ -14,6 +14,8 @@ use tranquil_pds::scheduled::{
 };
 use tranquil_pds::state::AppState;
 
+mod tls;
+
 #[derive(Parser)]
 #[command(name = "tranquil-pds", version = BUILD_VERSION, about = "Tranquil AT Protocol PDS")]
 struct Cli {
@@ -53,16 +55,19 @@ async fn main() -> ExitCode {
                         return ExitCode::FAILURE;
                     }
                 };
-                match config.validate(*ignore_secrets) {
-                    Ok(()) => {
-                        println!("Configuration is valid.");
-                        ExitCode::SUCCESS
-                    }
-                    Err(e) => {
-                        eprint!("{e}");
-                        ExitCode::FAILURE
-                    }
+                if let Err(e) = config.validate(*ignore_secrets) {
+                    eprint!("{e}");
+                    return ExitCode::FAILURE;
                 }
+                if !*ignore_secrets
+                    && let Some((cert, key)) = config.server.tls.material()
+                    && let Err(e) = tls::load_certified_key(cert, key)
+                {
+                    eprintln!("TLS material invalid: {e}");
+                    return ExitCode::FAILURE;
+                }
+                println!("Configuration is valid.");
+                ExitCode::SUCCESS
             }
         };
     }
@@ -110,19 +115,15 @@ async fn run() -> Result<(), Box<dyn std::error::Error>> {
 
     let mut state = AppState::new(shutdown.clone()).await?;
 
-    let signal_sender = if tranquil_config::get().signal.enabled {
-        let slot = Arc::new(tranquil_signal::SignalSlot::default());
-        state = state.with_signal_sender(slot.clone());
-        if let Some(provider) = &state.signal_store_provider
-            && let Some(client) = provider.load_signal_client(shutdown.clone()).await
-        {
-            slot.set_client(client).await;
-            info!("Signal device already linked");
-        }
-        Some(SignalSender::new(slot))
-    } else {
-        None
-    };
+    let signal_slot = Arc::new(tranquil_signal::SignalSlot::default());
+    state = state.with_signal_sender(signal_slot.clone());
+    if let Some(provider) = &state.signal_store_provider
+        && let Some(client) = provider.load_signal_client(shutdown.clone()).await
+    {
+        signal_slot.set_client(client).await;
+        info!("Signal device linked");
+    }
+    let signal_sender = SignalSender::new(signal_slot);
 
     tranquil_sync::listener::start_sequencer_listener(state.clone()).await;
 
@@ -141,11 +142,18 @@ async fn run() -> Result<(), Box<dyn std::error::Error>> {
 
     let cfg = tranquil_config::get();
 
-    if let Some(email_sender) = EmailSender::from_config(cfg) {
-        info!("Email comms enabled");
-        comms_service = comms_service.register_sender(email_sender);
-    } else {
-        warn!("Email comms disabled (MAIL_FROM_ADDRESS not set)");
+    match EmailSender::from_config(cfg) {
+        Ok(Some(email_sender)) => {
+            info!("Email comms enabled");
+            comms_service = comms_service.register_sender(email_sender);
+        }
+        Ok(None) => {
+            warn!("Email comms disabled (MAIL_FROM_ADDRESS unset)");
+        }
+        Err(e) => {
+            error!(error = %e, "Email configuration invalid");
+            return Err(e.into());
+        }
     }
 
     if let Some(discord_sender) = DiscordSender::from_config(cfg) {
@@ -220,10 +228,7 @@ async fn run() -> Result<(), Box<dyn std::error::Error>> {
         comms_service = comms_service.register_sender(telegram_sender);
     }
 
-    if let Some(sender) = signal_sender {
-        info!("Signal comms enabled");
-        comms_service = comms_service.register_sender(sender);
-    }
+    comms_service = comms_service.register_sender(signal_sender);
 
     let comms_handle = tokio::spawn(comms_service.run(shutdown.clone()));
 
@@ -281,11 +286,35 @@ async fn run() -> Result<(), Box<dyn std::error::Error>> {
         .await
         .map_err(|e| format!("Failed to bind to {}: {}", addr, e))?;
 
-    let server_handle = tokio::spawn(async move {
-        axum::serve(listener, app)
-            .with_graceful_shutdown(shutdown.clone().cancelled_owned())
-            .await
-    });
+    let server_handle = match cfg.server.tls.material() {
+        Some((cert_path, key_path)) => {
+            let initial = tls::load_certified_key(cert_path, key_path)
+                .map_err(|e| format!("Failed to load TLS material: {e}"))?;
+            let resolver = Arc::new(tls::ReloadableCertResolver::new(initial));
+            let server_config = Arc::new(
+                tls::build_server_config(resolver.clone())
+                    .map_err(|e| format!("Failed to build TLS configuration: {e}"))?,
+            );
+            tls::spawn_reload_handler(
+                resolver,
+                cert_path.to_string(),
+                key_path.to_string(),
+                shutdown.clone(),
+            );
+            info!("TLS termination enabled (h2, http/1.1), reload with SIGHUP");
+            let shutdown = shutdown.clone();
+            tokio::spawn(tls::serve_tls(listener, app, server_config, shutdown))
+        }
+        None => {
+            let make_service = app.into_make_service_with_connect_info::<SocketAddr>();
+            let shutdown = shutdown.clone();
+            tokio::spawn(async move {
+                axum::serve(listener, make_service)
+                    .with_graceful_shutdown(shutdown.cancelled_owned())
+                    .await
+            })
+        }
+    };
 
     if let Some((sender, app_id, webhook_url)) = deferred_discord_endpoint {
         tokio::spawn(async move {

crates/tranquil-server/src/tls.rs

@@ -0,0 +1,558 @@
+use std::io::BufReader;
+use std::net::SocketAddr;
+use std::sync::Arc;
+use std::time::Duration;
+
+use arc_swap::ArcSwap;
+use axum::Router;
+use axum::extract::ConnectInfo;
+use futures_util::StreamExt;
+use hyper::Request;
+use hyper::body::Incoming;
+use hyper_util::rt::{TokioExecutor, TokioIo};
+use hyper_util::server::conn::auto;
+use rustls::ServerConfig;
+use rustls::crypto::ring;
+use rustls::pki_types::{CertificateDer, PrivateKeyDer};
+use rustls::server::{ClientHello, ResolvesServerCert};
+use rustls::sign::CertifiedKey;
+use tokio::net::{TcpListener, TcpStream};
+use tokio::sync::{OwnedSemaphorePermit, Semaphore};
+use tokio_rustls::TlsAcceptor;
+use tokio_util::sync::CancellationToken;
+use tokio_util::task::TaskTracker;
+use tower::Service;
+use tracing::{debug, warn};
+
+const SHUTDOWN_GRACE: Duration = Duration::from_secs(10);
+const HANDSHAKE_TIMEOUT: Duration = Duration::from_secs(10);
+const ACCEPT_ERROR_BACKOFF: Duration = Duration::from_secs(1);
+const MAX_CONCURRENT_HANDSHAKES: usize = 512;
+
+#[derive(Debug, thiserror::Error)]
+pub enum TlsError {
+    #[error("reading {path}: {source}")]
+    Read {
+        path: String,
+        source: std::io::Error,
+    },
+    #[error("parsing {path}: {message}")]
+    Parse { path: String, message: String },
+    #[error("no certificates found in {0}")]
+    NoCertificates(String),
+    #[error("no private key found in {0}")]
+    NoPrivateKey(String),
+    #[error("unusable private key: {0}")]
+    SigningKey(String),
+    #[error("building server config: {0}")]
+    Config(String),
+    #[error("certificate and private key do not match: {0}")]
+    KeyMismatch(String),
+}
+
+pub struct ReloadableCertResolver {
+    current: ArcSwap<CertifiedKey>,
+}
+
+impl std::fmt::Debug for ReloadableCertResolver {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("ReloadableCertResolver")
+            .finish_non_exhaustive()
+    }
+}
+
+impl ReloadableCertResolver {
+    pub fn new(initial: CertifiedKey) -> Self {
+        Self {
+            current: ArcSwap::from_pointee(initial),
+        }
+    }
+
+    pub fn store(&self, key: CertifiedKey) {
+        self.current.store(Arc::new(key));
+    }
+}
+
+impl ResolvesServerCert for ReloadableCertResolver {
+    fn resolve(&self, _client_hello: ClientHello<'_>) -> Option<Arc<CertifiedKey>> {
+        Some(self.current.load_full())
+    }
+}
+
+pub fn load_certified_key(cert_path: &str, key_path: &str) -> Result<CertifiedKey, TlsError> {
+    let certs = load_certs(cert_path)?;
+    let key = load_private_key(key_path)?;
+    let signing_key =
+        ring::sign::any_supported_type(&key).map_err(|e| TlsError::SigningKey(e.to_string()))?;
+    let certified = CertifiedKey::new(certs, signing_key);
+    certified
+        .keys_match()
+        .map_err(|e| TlsError::KeyMismatch(e.to_string()))?;
+    Ok(certified)
+}
+
+fn load_certs(path: &str) -> Result<Vec<CertificateDer<'static>>, TlsError> {
+    let bytes = std::fs::read(path).map_err(|source| TlsError::Read {
+        path: path.to_string(),
+        source,
+    })?;
+    let mut reader = BufReader::new(bytes.as_slice());
+    let certs = rustls_pemfile::certs(&mut reader)
+        .collect::<Result<Vec<_>, _>>()
+        .map_err(|e| TlsError::Parse {
+            path: path.to_string(),
+            message: e.to_string(),
+        })?;
+    match certs.is_empty() {
+        true => Err(TlsError::NoCertificates(path.to_string())),
+        false => Ok(certs),
+    }
+}
+
+fn load_private_key(path: &str) -> Result<PrivateKeyDer<'static>, TlsError> {
+    let bytes = std::fs::read(path).map_err(|source| TlsError::Read {
+        path: path.to_string(),
+        source,
+    })?;
+    let mut reader = BufReader::new(bytes.as_slice());
+    rustls_pemfile::private_key(&mut reader)
+        .map_err(|e| TlsError::Parse {
+            path: path.to_string(),
+            message: e.to_string(),
+        })?
+        .ok_or_else(|| TlsError::NoPrivateKey(path.to_string()))
+}
+
+pub fn build_server_config(
+    resolver: Arc<ReloadableCertResolver>,
+) -> Result<ServerConfig, TlsError> {
+    let provider = Arc::new(ring::default_provider());
+    let mut config = ServerConfig::builder_with_provider(provider)
+        .with_safe_default_protocol_versions()
+        .map_err(|e| TlsError::Config(e.to_string()))?
+        .with_no_client_auth()
+        .with_cert_resolver(resolver);
+    config.alpn_protocols = vec![b"h2".to_vec(), b"http/1.1".to_vec()];
+    Ok(config)
+}
+
+pub fn spawn_reload_handler(
+    resolver: Arc<ReloadableCertResolver>,
+    cert_path: String,
+    key_path: String,
+    shutdown: CancellationToken,
+) {
+    #[cfg(unix)]
+    tokio::spawn(async move {
+        use tokio::signal::unix::{SignalKind, signal};
+        let mut hangup = match signal(SignalKind::hangup()) {
+            Ok(stream) => stream,
+            Err(e) => {
+                tracing::error!("Failed to install SIGHUP handler: {e}");
+                return;
+            }
+        };
+        loop {
+            tokio::select! {
+                _ = shutdown.cancelled() => break,
+                received = hangup.recv() => {
+                    if received.is_none() {
+                        break;
+                    }
+                    match load_certified_key(&cert_path, &key_path) {
+                        Ok(key) => {
+                            resolver.store(key);
+                            tracing::info!("TLS certificate and key reloaded");
+                        }
+                        Err(e) => {
+                            warn!("TLS reload failed, keeping existing certificate: {e}");
+                        }
+                    }
+                }
+            }
+        }
+    });
+
+    #[cfg(not(unix))]
+    let _ = (resolver, cert_path, key_path, shutdown);
+}
+
+fn is_connection_error(e: &std::io::Error) -> bool {
+    matches!(
+        e.kind(),
+        std::io::ErrorKind::ConnectionRefused
+            | std::io::ErrorKind::ConnectionAborted
+            | std::io::ErrorKind::ConnectionReset
+    )
+}
+
+pub async fn serve_tls(
+    listener: TcpListener,
+    app: Router,
+    server_config: Arc<ServerConfig>,
+    shutdown: CancellationToken,
+) -> std::io::Result<()> {
+    let acceptor = TlsAcceptor::from(server_config);
+    let tracker = TaskTracker::new();
+    let handshake_limiter = Arc::new(Semaphore::new(MAX_CONCURRENT_HANDSHAKES));
+
+    let connections = futures_util::stream::unfold(listener, |listener| async move {
+        Some((listener.accept().await, listener))
+    });
+
+    connections
+        .take_until(shutdown.clone().cancelled_owned())
+        .for_each(|accepted| {
+            let acceptor = acceptor.clone();
+            let app = app.clone();
+            let conn_shutdown = shutdown.clone();
+            let limiter = handshake_limiter.clone();
+            let tracker = &tracker;
+            async move {
+                match accepted {
+                    Ok((tcp, peer)) => {
+                        let permit = tokio::select! {
+                            biased;
+                            _ = conn_shutdown.cancelled() => return,
+                            permit = limiter.acquire_owned() => match permit {
+                                Ok(permit) => permit,
+                                Err(_) => return,
+                            },
+                        };
+                        tracker.spawn(serve_connection(
+                            acceptor,
+                            app,
+                            tcp,
+                            peer,
+                            conn_shutdown,
+                            permit,
+                        ));
+                    }
+                    Err(e) if is_connection_error(&e) => {
+                        debug!("TLS accept connection error: {e}");
+                    }
+                    Err(e) => {
+                        warn!(
+                            "TLS accept failed, pausing {ACCEPT_ERROR_BACKOFF:?} before retry: {e}"
+                        );
+                        tokio::select! {
+                            _ = tokio::time::sleep(ACCEPT_ERROR_BACKOFF) => {}
+                            _ = conn_shutdown.cancelled() => {}
+                        }
+                    }
+                }
+            }
+        })
+        .await;
+
+    tracker.close();
+    tracker.wait().await;
+    Ok(())
+}
+
+async fn serve_connection(
+    acceptor: TlsAcceptor,
+    app: Router,
+    tcp: TcpStream,
+    peer: SocketAddr,
+    shutdown: CancellationToken,
+    handshake_permit: OwnedSemaphorePermit,
+) {
+    let tls_stream = tokio::select! {
+        result = tokio::time::timeout(HANDSHAKE_TIMEOUT, acceptor.accept(tcp)) => match result {
+            Ok(Ok(stream)) => stream,
+            Ok(Err(e)) => {
+                debug!("TLS handshake with {peer} failed: {e}");
+                return;
+            }
+            Err(_) => {
+                debug!("TLS handshake with {peer} timed out after {HANDSHAKE_TIMEOUT:?}");
+                return;
+            }
+        },
+        _ = shutdown.cancelled() => {
+            debug!("shutdown during TLS handshake with {peer}");
+            return;
+        }
+    };
+    drop(handshake_permit);
+
+    let service = hyper::service::service_fn(move |mut request: Request<Incoming>| {
+        request.extensions_mut().insert(ConnectInfo(peer));
+        app.clone().call(request)
+    });
+
+    let builder = auto::Builder::new(TokioExecutor::new());
+    let connection = builder.serve_connection_with_upgrades(TokioIo::new(tls_stream), service);
+    tokio::pin!(connection);
+
+    tokio::select! {
+        result = connection.as_mut() => {
+            if let Err(e) = result {
+                debug!("connection from {peer} ended: {e}");
+            }
+        }
+        _ = shutdown.cancelled() => {
+            connection.as_mut().graceful_shutdown();
+            match tokio::time::timeout(SHUTDOWN_GRACE, connection.as_mut()).await {
+                Ok(Err(e)) => debug!("connection from {peer} ended during shutdown: {e}"),
+                Err(_) => debug!("connection from {peer} did not drain within grace, dropping"),
+                Ok(Ok(())) => {}
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::sync::atomic::{AtomicU32, Ordering};
+
+    const CERT_1: &str = "-----BEGIN CERTIFICATE-----\n\
+MIIBrTCCAVKgAwIBAgIUWIlnxLpgk7qp8We8ya6UW1I7p0MwCgYIKoZIzj0EAwIw\n\
+FDESMBAGA1UEAwwJbG9jYWxob3N0MB4XDTI2MDUyNjEyMTQyMloXDTM2MDUyMzEy\n\
+MTQyMlowFDESMBAGA1UEAwwJbG9jYWxob3N0MFkwEwYHKoZIzj0CAQYIKoZIzj0D\n\
+AQcDQgAEgq5UvmRilQh66D5C+78TdULpCuIrI7dtvBB589iJK8Gq14SW9ewkbiWD\n\
+QrXirV47GPzRnODrDIqFSCa4yH+dz6OBgTB/MB0GA1UdDgQWBBSVcvSAd4XB3SCU\n\
+e8MKSOm9i6yigjAfBgNVHSMEGDAWgBSVcvSAd4XB3SCUe8MKSOm9i6yigjAPBgNV\n\
+HRMBAf8EBTADAQH/MCwGA1UdEQQlMCOCCWxvY2FsaG9zdIcQAAAAAAAAAAAAAAAA\n\
+AAAAAYcEfwAAATAKBggqhkjOPQQDAgNJADBGAiEA6pIKG7uRbgzuOCDY1Rm+QCuF\n\
+/UTOjWKrfZhoDnXP+swCIQCV7p6vRSt0GnbRzIIcN8UM68cXDZX+Nk0XofZaN217\n\
+mg==\n\
+-----END CERTIFICATE-----\n";
+
+    const KEY_1: &str = "-----BEGIN PRIVATE KEY-----\n\
+MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQgMobX2BajiDVtV5Ti\n\
+kiJ8qEbduI0HvT/qORtLjjCXQ5OhRANCAASCrlS+ZGKVCHroPkL7vxN1QukK4isj\n\
+t228EHnz2IkrwarXhJb17CRuJYNCteKtXjsY/NGc4OsMioVIJrjIf53P\n\
+-----END PRIVATE KEY-----\n";
+
+    const CERT_2: &str = "-----BEGIN CERTIFICATE-----\n\
+MIIBrDCCAVKgAwIBAgIUJjaLQsKBClkIbtSmDK9vZ9gCrbQwCgYIKoZIzj0EAwIw\n\
+FDESMBAGA1UEAwwJbG9jYWxob3N0MB4XDTI2MDUyNjEyMTQyMloXDTM2MDUyMzEy\n\
+MTQyMlowFDESMBAGA1UEAwwJbG9jYWxob3N0MFkwEwYHKoZIzj0CAQYIKoZIzj0D\n\
+AQcDQgAEI6ljji6CAII88C48Hu7kzEjnV9gMVs8v8Oom04PfcXPR/GSUc0MYz3y4\n\
+LXZC2yNJl40ynzuXNhisk/mQjYbKYaOBgTB/MB0GA1UdDgQWBBTqLGV3rtN9hiuR\n\
+oHUPNnvkwz/DbDAfBgNVHSMEGDAWgBTqLGV3rtN9hiuRoHUPNnvkwz/DbDAPBgNV\n\
+HRMBAf8EBTADAQH/MCwGA1UdEQQlMCOCCWxvY2FsaG9zdIcQAAAAAAAAAAAAAAAA\n\
+AAAAAYcEfwAAATAKBggqhkjOPQQDAgNIADBFAiAMVxuI5vyDYi1RtsyuiB+sIl1D\n\
+SdSOaWIgtxPVs5E0CQIhAIrrra+TPrmE8JrjwJBlsONl3oTlOcfDA9WP/FnYbHuv\n\
+-----END CERTIFICATE-----\n";
+
+    const KEY_2: &str = "-----BEGIN PRIVATE KEY-----\n\
+MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQgyBJsGRjta0gqCcBH\n\
+LI5Q1uj42QD1KUfmkOj+o4jlDlmhRANCAAQjqWOOLoIAgjzwLjwe7uTMSOdX2AxW\n\
+zy/w6ibTg99xc9H8ZJRzQxjPfLgtdkLbI0mXjTKfO5c2GKyT+ZCNhsph\n\
+-----END PRIVATE KEY-----\n";
+
+    #[derive(Debug)]
+    struct AcceptAnyServerCert;
+
+    impl rustls::client::danger::ServerCertVerifier for AcceptAnyServerCert {
+        fn verify_server_cert(
+            &self,
+            _end_entity: &rustls::pki_types::CertificateDer<'_>,
+            _intermediates: &[rustls::pki_types::CertificateDer<'_>],
+            _server_name: &rustls::pki_types::ServerName<'_>,
+            _ocsp_response: &[u8],
+            _now: rustls::pki_types::UnixTime,
+        ) -> Result<rustls::client::danger::ServerCertVerified, rustls::Error> {
+            Ok(rustls::client::danger::ServerCertVerified::assertion())
+        }
+
+        fn verify_tls12_signature(
+            &self,
+            _message: &[u8],
+            _cert: &rustls::pki_types::CertificateDer<'_>,
+            _dss: &rustls::DigitallySignedStruct,
+        ) -> Result<rustls::client::danger::HandshakeSignatureValid, rustls::Error> {
+            Ok(rustls::client::danger::HandshakeSignatureValid::assertion())
+        }
+
+        fn verify_tls13_signature(
+            &self,
+            _message: &[u8],
+            _cert: &rustls::pki_types::CertificateDer<'_>,
+            _dss: &rustls::DigitallySignedStruct,
+        ) -> Result<rustls::client::danger::HandshakeSignatureValid, rustls::Error> {
+            Ok(rustls::client::danger::HandshakeSignatureValid::assertion())
+        }
+
+        fn supported_verify_schemes(&self) -> Vec<rustls::SignatureScheme> {
+            ring::default_provider()
+                .signature_verification_algorithms
+                .supported_schemes()
+        }
+    }
+
+    fn write_temp(contents: &str) -> std::path::PathBuf {
+        static COUNTER: AtomicU32 = AtomicU32::new(0);
+        let unique = COUNTER.fetch_add(1, Ordering::Relaxed);
+        let path = std::env::temp_dir().join(format!(
+            "tranquil_tls_test_{}_{unique}.pem",
+            std::process::id()
+        ));
+        std::fs::write(&path, contents).expect("write temp pem");
+        path
+    }
+
+    #[test]
+    fn loads_certificate_and_key() {
+        let cert = write_temp(CERT_1);
+        let key = write_temp(KEY_1);
+        let certified = load_certified_key(cert.to_str().unwrap(), key.to_str().unwrap())
+            .expect("load certified key");
+        assert_eq!(certified.cert.len(), 1);
+    }
+
+    #[test]
+    fn missing_certificate_file_is_read_error() {
+        let result = load_certs("/nonexistent/tranquil/cert.pem");
+        assert!(matches!(result, Err(TlsError::Read { .. })));
+    }
+
+    #[test]
+    fn empty_certificate_file_has_no_certificates() {
+        let cert = write_temp("");
+        let result = load_certs(cert.to_str().unwrap());
+        assert!(matches!(result, Err(TlsError::NoCertificates(_))));
+    }
+
+    #[test]
+    fn certificate_without_key_is_missing_key() {
+        let cert_only = write_temp(CERT_1);
+        let result = load_private_key(cert_only.to_str().unwrap());
+        assert!(matches!(result, Err(TlsError::NoPrivateKey(_))));
+    }
+
+    #[test]
+    fn server_config_advertises_h2_and_http1() {
+        let cert = write_temp(CERT_1);
+        let key = write_temp(KEY_1);
+        let certified = load_certified_key(cert.to_str().unwrap(), key.to_str().unwrap()).unwrap();
+        let resolver = Arc::new(ReloadableCertResolver::new(certified));
+        let config = build_server_config(resolver).expect("build server config");
+        assert_eq!(
+            config.alpn_protocols,
+            vec![b"h2".to_vec(), b"http/1.1".to_vec()]
+        );
+    }
+
+    #[test]
+    fn reload_swaps_the_served_certificate() {
+        let cert1 = write_temp(CERT_1);
+        let key1 = write_temp(KEY_1);
+        let cert2 = write_temp(CERT_2);
+        let key2 = write_temp(KEY_2);
+
+        let first = load_certified_key(cert1.to_str().unwrap(), key1.to_str().unwrap()).unwrap();
+        let resolver = ReloadableCertResolver::new(first);
+        let before = resolver.current.load_full().cert.clone();
+
+        let second = load_certified_key(cert2.to_str().unwrap(), key2.to_str().unwrap()).unwrap();
+        resolver.store(second);
+        let after = resolver.current.load_full().cert.clone();
+
+        assert_ne!(before, after);
+    }
+
+    #[tokio::test]
+    async fn terminates_tls_over_ipv6_and_negotiates_alpn() {
+        use rustls::pki_types::ServerName;
+        use tokio::io::{AsyncReadExt, AsyncWriteExt};
+        use tokio_rustls::TlsConnector;
+
+        let cert = write_temp(CERT_1);
+        let key = write_temp(KEY_1);
+        let certified = load_certified_key(cert.to_str().unwrap(), key.to_str().unwrap()).unwrap();
+        let resolver = Arc::new(ReloadableCertResolver::new(certified));
+        let server_config = Arc::new(build_server_config(resolver).unwrap());
+
+        let app = Router::new().route("/", axum::routing::get(|| async { "ok" }));
+        let listener = TcpListener::bind("[::1]:0").await.unwrap();
+        let addr = listener.local_addr().unwrap();
+        assert!(addr.is_ipv6(), "expected ipv6 bind, got {addr}");
+
+        let shutdown = CancellationToken::new();
+        let server = tokio::spawn(serve_tls(listener, app, server_config, shutdown.clone()));
+
+        let mut client_config =
+            rustls::ClientConfig::builder_with_provider(Arc::new(ring::default_provider()))
+                .with_safe_default_protocol_versions()
+                .unwrap()
+                .dangerous()
+                .with_custom_certificate_verifier(Arc::new(AcceptAnyServerCert))
+                .with_no_client_auth();
+        client_config.alpn_protocols = vec![b"http/1.1".to_vec()];
+        let connector = TlsConnector::from(Arc::new(client_config));
+        let server_name = ServerName::try_from("localhost").unwrap();
+
+        let tcp = TcpStream::connect(addr).await.unwrap();
+        let mut tls = connector.connect(server_name, tcp).await.unwrap();
+
+        let alpn = tls.get_ref().1.alpn_protocol().map(<[u8]>::to_vec);
+        assert_eq!(alpn, Some(b"http/1.1".to_vec()));
+
+        tls.write_all(b"GET / HTTP/1.1\r\nHost: localhost\r\nConnection: close\r\n\r\n")
+            .await
+            .unwrap();
+        let mut response = Vec::new();
+        tls.read_to_end(&mut response).await.unwrap();
+        let text = String::from_utf8_lossy(&response);
+        assert!(
+            text.starts_with("HTTP/1.1 200"),
+            "unexpected response: {text}"
+        );
+        assert!(text.trim_end().ends_with("ok"), "unexpected body: {text}");
+
+        shutdown.cancel();
+        let _ = tokio::time::timeout(Duration::from_secs(5), server).await;
+    }
+
+    #[test]
+    fn mismatched_cert_and_key_is_rejected() {
+        let cert = write_temp(CERT_1);
+        let key = write_temp(KEY_2);
+        let result = load_certified_key(cert.to_str().unwrap(), key.to_str().unwrap());
+        assert!(matches!(result, Err(TlsError::KeyMismatch(_))));
+    }
+
+    #[tokio::test]
+    async fn negotiates_h2_when_client_offers_only_h2() {
+        use rustls::pki_types::ServerName;
+        use tokio_rustls::TlsConnector;
+
+        let cert = write_temp(CERT_1);
+        let key = write_temp(KEY_1);
+        let certified = load_certified_key(cert.to_str().unwrap(), key.to_str().unwrap()).unwrap();
+        let resolver = Arc::new(ReloadableCertResolver::new(certified));
+        let server_config = Arc::new(build_server_config(resolver).unwrap());
+
+        let app = Router::new().route("/", axum::routing::get(|| async { "ok" }));
+        let listener = TcpListener::bind("[::1]:0").await.unwrap();
+        let addr = listener.local_addr().unwrap();
+
+        let shutdown = CancellationToken::new();
+        let server = tokio::spawn(serve_tls(listener, app, server_config, shutdown.clone()));
+
+        let mut client_config =
+            rustls::ClientConfig::builder_with_provider(Arc::new(ring::default_provider()))
+                .with_safe_default_protocol_versions()
+                .unwrap()
+                .dangerous()
+                .with_custom_certificate_verifier(Arc::new(AcceptAnyServerCert))
+                .with_no_client_auth();
+        client_config.alpn_protocols = vec![b"h2".to_vec()];
+        let connector = TlsConnector::from(Arc::new(client_config));
+        let server_name = ServerName::try_from("localhost").unwrap();
+
+        let tcp = TcpStream::connect(addr).await.unwrap();
+        let tls = connector.connect(server_name, tcp).await.unwrap();
+
+        let alpn = tls.get_ref().1.alpn_protocol().map(<[u8]>::to_vec);
+        assert_eq!(alpn, Some(b"h2".to_vec()));
+
+        shutdown.cancel();
+        let _ = tokio::time::timeout(Duration::from_secs(5), server).await;
+    }
+}

crates/tranquil-signal/src/client.rs

@@ -352,7 +352,7 @@ impl SignalClient {
         let manager = init_rx
             .await
             .ok()?
-            .map_err(|e| tracing::error!(error = %e, "failed to load registered signal manager"))
+            .map_err(|e| tracing::debug!(error = %e, "no linked signal device"))
             .ok()?;
 
         Self::from_manager(manager, shutdown)

crates/tranquil-store/fuzz/fuzz_targets/gauntlet_micro.rs

@@ -76,6 +76,7 @@ fn tiny_config() -> GauntletConfig {
         },
         eventlog: None,
         writer_concurrency: WriterConcurrency(1),
+        tolerate_op_errors: false,
     }
 }
 

crates/tranquil-store/src/bin/tranquil_gauntlet.rs

@@ -64,6 +64,16 @@ enum Cmd {
         #[arg(long)]
         config: Option<PathBuf>,
 
+        /// Tempdir parent for `IoBackend::Real` seeds only - ignored for
+        /// flaky-mount and simulated backends. Repeatable; each rayon worker
+        /// thread is pinned to one root so concurrent seeds on different
+        /// threads land on different mounts. Default `/tmp`. Also reads
+        /// colon-separated paths from `GAUNTLET_SCRATCH_ROOTS`. Set
+        /// `RAYON_NUM_THREADS=N` to cap workers; for full distribution pass
+        /// one root per worker.
+        #[arg(long)]
+        scratch_root: Vec<PathBuf>,
+
         /// Skip shrinking when dumping regressions.
         #[arg(long)]
         no_shrink: bool,
@@ -95,6 +105,13 @@ enum Cmd {
         #[arg(long)]
         dump_regressions: Option<PathBuf>,
 
+        /// Same as `farm --scratch-root`: tempdir parent for
+        /// `IoBackend::Real` seeds only, pinned per worker thread. Ignored
+        /// for flaky-mount and simulated backends. Repeatable; reads
+        /// colon-separated paths from `GAUNTLET_SCRATCH_ROOTS`.
+        #[arg(long)]
+        scratch_root: Vec<PathBuf>,
+
         /// Skip shrinking when dumping regressions.
         #[arg(long)]
         no_shrink: bool,
@@ -159,6 +176,8 @@ struct ConfigFile {
     #[serde(default)]
     dump_regressions: Option<PathBuf>,
     #[serde(default)]
+    scratch_roots: Vec<PathBuf>,
+    #[serde(default)]
     overrides: ConfigOverrides,
 }
 
@@ -178,6 +197,8 @@ struct SweepConfigFile {
     #[serde(default)]
     dump_regressions: Option<PathBuf>,
     #[serde(default)]
+    scratch_roots: Vec<PathBuf>,
+    #[serde(default)]
     base_overrides: ConfigOverrides,
     #[serde(default)]
     axes: SweepAxes,
@@ -405,6 +426,7 @@ struct FarmPlan {
     seeds: u64,
     hours: Option<f64>,
     dump_regressions: Option<PathBuf>,
+    scratch_roots: Vec<PathBuf>,
     overrides: ConfigOverrides,
     shrink: bool,
     shrink_budget: usize,
@@ -418,6 +440,7 @@ fn resolve_farm(
     hours: Option<f64>,
     dump_regressions: Option<PathBuf>,
     config: Option<PathBuf>,
+    scratch_root: Vec<PathBuf>,
     shrink: bool,
     shrink_budget: usize,
 ) -> Result<FarmPlan, String> {
@@ -443,6 +466,11 @@ fn resolve_farm(
     }
     let dump_regressions =
         dump_regressions.or_else(|| file.as_ref().and_then(|f| f.dump_regressions.clone()));
+    let file_scratch_roots = file
+        .as_ref()
+        .map(|f| f.scratch_roots.clone())
+        .unwrap_or_default();
+    let scratch_roots = resolve_scratch_roots(scratch_root, file_scratch_roots)?;
     let overrides = file.map(|f| f.overrides).unwrap_or_default();
     Ok(FarmPlan {
         scenario,
@@ -450,12 +478,50 @@ fn resolve_farm(
         seeds,
         hours,
         dump_regressions,
+        scratch_roots,
         overrides,
         shrink,
         shrink_budget,
     })
 }
 
+const SCRATCH_ROOTS_ENV: &str = "GAUNTLET_SCRATCH_ROOTS";
+
+fn resolve_scratch_roots(
+    cli: Vec<PathBuf>,
+    config_file: Vec<PathBuf>,
+) -> Result<Vec<PathBuf>, String> {
+    let env_roots: Vec<PathBuf> = std::env::var(SCRATCH_ROOTS_ENV)
+        .ok()
+        .filter(|s| !s.is_empty())
+        .map(|s| s.split(':').map(PathBuf::from).collect())
+        .unwrap_or_default();
+    let candidate: Vec<PathBuf> = if !cli.is_empty() {
+        cli
+    } else if !config_file.is_empty() {
+        config_file
+    } else {
+        env_roots
+    };
+    candidate
+        .into_iter()
+        .map(|p| validate_scratch_root(&p).map(|_| p))
+        .collect()
+}
+
+fn validate_scratch_root(path: &Path) -> Result<(), String> {
+    match path.metadata() {
+        Ok(m) if m.is_dir() => {}
+        Ok(_) => return Err(format!("scratch root not a directory: {}", path.display())),
+        Err(e) => return Err(format!("scratch root {}: {e}", path.display())),
+    }
+    tempfile::Builder::new()
+        .prefix(".tranquil-gauntlet-probe-")
+        .tempfile_in(path)
+        .map(|_| ())
+        .map_err(|e| format!("scratch root {} not writable: {e}", path.display()))
+}
+
 fn validate_hours(h: f64) -> Result<(), String> {
     if !h.is_finite() || h <= 0.0 {
         return Err(format!("invalid --hours={h}: must be positive and finite"));
@@ -564,6 +630,7 @@ fn main() -> ExitCode {
             hours,
             dump_regressions,
             config,
+            scratch_root,
             no_shrink,
             shrink_budget,
         } => {
@@ -574,6 +641,7 @@ fn main() -> ExitCode {
                 hours,
                 dump_regressions,
                 config,
+                scratch_root,
                 !no_shrink,
                 shrink_budget,
             ) {
@@ -625,6 +693,7 @@ fn main() -> ExitCode {
             seed_start,
             seeds,
             dump_regressions,
+            scratch_root,
             no_shrink,
             shrink_budget,
             max_runs,
@@ -634,6 +703,7 @@ fn main() -> ExitCode {
                 seed_start,
                 seeds,
                 dump_regressions,
+                scratch_root,
                 !no_shrink,
                 shrink_budget,
                 max_runs,
@@ -659,17 +729,20 @@ struct SweepPlan {
     seed_start: u64,
     seeds: u64,
     dump_regressions: Option<PathBuf>,
+    scratch_roots: Vec<PathBuf>,
     shrink: bool,
     shrink_budget: usize,
     base_overrides: ConfigOverrides,
     axes: Vec<SweepAxisValues>,
 }
 
+#[allow(clippy::too_many_arguments)]
 fn resolve_sweep(
     config: PathBuf,
     seed_start: Option<u64>,
     seeds: Option<u64>,
     dump_regressions: Option<PathBuf>,
+    scratch_root: Vec<PathBuf>,
     shrink: bool,
     shrink_budget: usize,
     max_runs: u64,
@@ -687,6 +760,7 @@ fn resolve_sweep(
         return Err("--shrink-budget must be greater than zero".to_string());
     }
     let dump_regressions = dump_regressions.or(file.dump_regressions.clone());
+    let scratch_roots = resolve_scratch_roots(scratch_root, file.scratch_roots.clone())?;
     let axes = file.axes.axis_values();
     if axes.is_empty() {
         return Err("sweep produced no combinations".to_string());
@@ -705,6 +779,7 @@ fn resolve_sweep(
         seed_start,
         seeds,
         dump_regressions,
+        scratch_roots,
         shrink,
         shrink_budget,
         base_overrides: file.base_overrides,
@@ -749,6 +824,7 @@ fn run_sweep(plan: SweepPlan, rt: &Runtime, interrupt: Arc<AtomicBool>) -> ExitC
         seed_start,
         seeds,
         dump_regressions,
+        scratch_roots,
         shrink,
         shrink_budget,
         base_overrides,
@@ -782,12 +858,13 @@ fn run_sweep(plan: SweepPlan, rt: &Runtime, interrupt: Arc<AtomicBool>) -> ExitC
         axis_values.apply_to(&mut overrides);
         let combo_start = Instant::now();
         let overrides_for_farm = overrides.clone();
-        let reports = farm::run_many_timed(
+        let reports = farm::run_many_timed_with_scratch_roots(
             move |s| {
                 let mut cfg = config_for(scenario, s);
                 overrides_for_farm.apply_to(&mut cfg);
                 cfg
             },
+            &scratch_roots,
             (seed_start..end).map(Seed),
         );
         let combo_wall = combo_start.elapsed();
@@ -840,6 +917,7 @@ fn run_farm(plan: FarmPlan, rt: &Runtime, interrupt: Arc<AtomicBool>) -> ExitCod
         seeds,
         hours,
         dump_regressions,
+        scratch_roots,
         overrides,
         shrink,
         shrink_budget,
@@ -871,12 +949,13 @@ fn run_farm(plan: FarmPlan, rt: &Runtime, interrupt: Arc<AtomicBool>) -> ExitCod
         };
         let overrides_ref = &overrides;
         let batch_start = Instant::now();
-        let reports = farm::run_many_timed(
+        let reports = farm::run_many_timed_with_scratch_roots(
             |s| {
                 let mut cfg = config_for(scenario, s);
                 overrides_ref.apply_to(&mut cfg);
                 cfg
             },
+            &scratch_roots,
             (next_seed..end).map(Seed),
         );
         let batch_wall = batch_start.elapsed();

crates/tranquil-store/src/blockstore/compaction.rs

@@ -7,7 +7,9 @@ use super::group_commit::{ActiveFileSet, FileIdAllocator};
 use super::hash_index::{BlockIndex, BlockIndexError};
 use super::hint::{HintFileWriter, hint_file_path};
 use super::manager::DataFileManager;
-use super::types::{BlockLocation, CidBytes, CommitEpoch, CompactionResult, DataFileId};
+use super::types::{
+    BlockLocation, CidBytes, CommitEpoch, CompactionResult, CompactionStats, DataFileId,
+};
 
 #[derive(Debug)]
 pub enum CompactionError {
@@ -68,7 +70,13 @@ pub(super) fn compact_on_writer_thread<S: StorageIO>(
         return Err(CompactionError::ActiveFileCannotBeCompacted);
     }
 
-    let source_handle = manager.open_for_read(source_file_id)?;
+    let source_handle = match manager.open_for_read(source_file_id) {
+        Ok(handle) => handle,
+        Err(e) if e.kind() == io::ErrorKind::NotFound => {
+            return purge_phantom_file(manager, index, hint_positions, epoch, source_file_id);
+        }
+        Err(e) => return Err(CompactionError::Io(e)),
+    };
     let source_size = manager.io().file_size(source_handle.fd())?;
 
     let new_file_id = file_ids.allocate();
@@ -92,10 +100,16 @@ pub(super) fn compact_on_writer_thread<S: StorageIO>(
                 .ok();
             Err(e)
         }
-        Ok((new_size, live_count, dead_count)) => {
-            if let Err(e) = index.write_checkpoint(epoch.current(), hint_positions) {
-                tracing::warn!(error = %e, "pre-delete checkpoint failed during compaction");
+        Ok((new_size, live_count, dead_count, new_hint_offset)) => {
+            match live_count {
+                0 => hint_positions.forget_extra(new_file_id),
+                _ => hint_positions.record_extra(new_file_id, new_hint_offset),
             }
+            hint_positions.forget_extra(source_file_id);
+
+            index
+                .write_checkpoint(epoch.current(), hint_positions)
+                .map_err(CompactionError::Io)?;
 
             manager.delete_data_file(source_file_id)?;
             manager
@@ -124,18 +138,51 @@ pub(super) fn compact_on_writer_thread<S: StorageIO>(
                 "compaction complete"
             );
 
-            Ok(CompactionResult {
+            Ok(CompactionResult::Compacted(CompactionStats {
                 file_id: source_file_id,
                 old_size: source_size,
                 new_size,
                 live_blocks: live_count,
                 dead_blocks: dead_count,
                 reclaimed_bytes,
-            })
+            }))
         }
     }
 }
 
+fn purge_phantom_file<S: StorageIO>(
+    manager: &DataFileManager<S>,
+    index: &BlockIndex,
+    hint_positions: &super::group_commit::ShardHintPositions,
+    epoch: &super::types::EpochCounter,
+    source_file_id: DataFileId,
+) -> Result<CompactionResult, CompactionError> {
+    let phantom_blocks = index.purge_by_file_id(source_file_id);
+
+    tracing::warn!(
+        file_id = %source_file_id,
+        phantom_blocks,
+        "source data file missing on disk, purged phantom index entries"
+    );
+
+    hint_positions.forget_extra(source_file_id);
+
+    manager
+        .io()
+        .delete(&hint_file_path(manager.data_dir(), source_file_id))
+        .ok();
+    manager.io().sync_dir(manager.data_dir()).ok();
+
+    index
+        .write_checkpoint(epoch.current(), hint_positions)
+        .map_err(CompactionError::Io)?;
+
+    Ok(CompactionResult::Purged {
+        file_id: source_file_id,
+        phantom_blocks,
+    })
+}
+
 fn stream_compact<S: StorageIO>(
     manager: &DataFileManager<S>,
     index: &BlockIndex,
@@ -144,7 +191,7 @@ fn stream_compact<S: StorageIO>(
     new_file_id: DataFileId,
     current_epoch: CommitEpoch,
     grace_period_ms: u64,
-) -> Result<(u64, u64, u64), CompactionError> {
+) -> Result<(u64, u64, u64, super::types::HintOffset), CompactionError> {
     let mut reader = DataFileReader::open(manager.io(), source_fd)?;
     let now = crate::wall_clock_ms();
 
@@ -222,8 +269,10 @@ fn stream_compact<S: StorageIO>(
                 .io()
                 .sync_dir(manager.data_dir())
                 .map_err(CompactionError::from)
-        });
+        })
+        .and_then(|()| manager.io().barrier().map_err(CompactionError::from));
 
+    let final_hint_offset = hint_writer.position();
     let _ = manager.io().close(hint_fd);
 
     finalize_result?;
@@ -232,5 +281,5 @@ fn stream_compact<S: StorageIO>(
 
     index.apply_compaction(&relocations, &dead_cids);
 
-    Ok((new_size, live_count, dead_count))
+    Ok((new_size, live_count, dead_count, final_hint_offset))
 }

crates/tranquil-store/src/blockstore/group_commit.rs

@@ -74,30 +74,49 @@ impl ActiveFileSet {
 }
 
 pub struct ShardHintPositions {
-    positions: RwLock<Vec<(DataFileId, HintOffset)>>,
+    shard_positions: RwLock<Vec<(DataFileId, HintOffset)>>,
+    extra_positions: RwLock<HashMap<DataFileId, HintOffset>>,
 }
 
 impl ShardHintPositions {
     pub fn new(shard_count: u8) -> Self {
         Self {
-            positions: RwLock::new(
+            shard_positions: RwLock::new(
                 (0..shard_count as usize)
                     .map(|_| (DataFileId::new(0), HintOffset::new(0)))
                     .collect(),
             ),
+            extra_positions: RwLock::new(HashMap::new()),
         }
     }
 
     pub fn update(&self, shard_id: ShardId, file_id: DataFileId, offset: HintOffset) {
-        let mut positions = self.positions.write();
+        let mut positions = self.shard_positions.write();
         let idx = shard_id.as_usize();
         if idx < positions.len() {
             positions[idx] = (file_id, offset);
         }
     }
 
+    pub fn record_extra(&self, file_id: DataFileId, offset: HintOffset) {
+        self.extra_positions.write().insert(file_id, offset);
+    }
+
+    pub fn forget_extra(&self, file_id: DataFileId) {
+        self.extra_positions.write().remove(&file_id);
+    }
+
     pub fn snapshot(&self) -> CheckpointPositions {
-        CheckpointPositions(self.positions.read().clone())
+        let shard = self.shard_positions.read().clone();
+        let extra = self.extra_positions.read().clone();
+        debug_assert!(
+            shard
+                .iter()
+                .filter(|(fid, _)| fid.raw() != 0)
+                .all(|(fid, _)| !extra.contains_key(fid)),
+            "shard_positions and extra_positions must not overlap on the same DataFileId"
+        );
+        CheckpointPositions(shard.into_iter().chain(extra).collect())
     }
 }
 
@@ -1343,6 +1362,10 @@ fn process_batch<S: StorageIO>(
         )
         .map_err(|e| rollback_on_err(CommitError::from(e)))?;
     hint_writer.sync().map_err(|e| rollback_on_err(e.into()))?;
+    manager
+        .io()
+        .barrier()
+        .map_err(|e| rollback_on_err(e.into()))?;
     let sync_nanos = t.elapsed().as_nanos() as u64;
 
     if !rotations.is_empty() {

crates/tranquil-store/src/blockstore/hash_index.rs

@@ -606,6 +606,34 @@ impl HashTable {
         });
     }
 
+    pub fn cids_in_file(&self, file_id: DataFileId) -> Vec<CidBytes> {
+        self.iter()
+            .filter(|s| s.file_id == file_id)
+            .map(|s| s.cid)
+            .collect()
+    }
+
+    pub fn purge_by_file_id(&mut self, file_id: DataFileId) -> u64 {
+        let victims: Vec<(CidBytes, RefCount)> = self
+            .iter()
+            .filter(|s| s.file_id == file_id)
+            .map(|s| (s.cid, s.refcount))
+            .collect();
+
+        let live_discarded = victims.iter().filter(|(_, rc)| !rc.is_zero()).count();
+        if live_discarded > 0 {
+            tracing::warn!(
+                file_id = %file_id,
+                live_discarded,
+                total_purged = victims.len(),
+                "discarding live index entries for missing data file"
+            );
+        }
+
+        let removed = victims.iter().filter(|(cid, _)| self.remove(cid)).count();
+        u64::try_from(removed).unwrap_or(u64::MAX)
+    }
+
     pub fn cleanup_stale_gc(&mut self) -> u64 {
         self.slots
             .iter_mut()
@@ -1503,6 +1531,14 @@ impl BlockIndex {
             })
     }
 
+    pub fn cids_in_file(&self, file_id: DataFileId) -> Vec<CidBytes> {
+        self.table.read().cids_in_file(file_id)
+    }
+
+    pub fn purge_by_file_id(&self, file_id: DataFileId) -> u64 {
+        self.table.write().purge_by_file_id(file_id)
+    }
+
     pub fn read_write_cursor(&self) -> Option<WriteCursor> {
         self.table.read().write_cursor()
     }

crates/tranquil-store/src/blockstore/mod.rs

@@ -27,11 +27,11 @@ pub use hint::{
 pub use manager::{CachedHandle, DEFAULT_MAX_FILE_SIZE, DataFileManager};
 pub use reader::{BlockStoreReader, ReadError};
 pub use store::QuiesceGuard;
-pub use store::{BlockStoreConfig, DEFAULT_SHARD_COUNT, TranquilBlockStore};
+pub use store::{BlockStoreConfig, DEFAULT_SHARD_COUNT, OpenRetryPolicy, TranquilBlockStore};
 pub use types::{
     BlockLength, BlockLocation, BlockOffset, BlockstoreSnapshot, CidBytes, CollectionResult,
-    CommitEpoch, CompactionResult, DataFileId, EpochCounter, HintOffset, IndexEntry, LivenessInfo,
-    MAX_BLOCK_SIZE, RefCount, ShardId, WallClockMs, WriteCursor,
+    CommitEpoch, CompactionResult, CompactionStats, DataFileId, EpochCounter, HintOffset,
+    IndexEntry, LivenessInfo, MAX_BLOCK_SIZE, RefCount, ShardId, WallClockMs, WriteCursor,
 };
 
 use std::io;

crates/tranquil-store/src/blockstore/store.rs

@@ -1,7 +1,9 @@
 use std::collections::HashMap;
 use std::io;
+use std::num::NonZeroU8;
 use std::path::{Path, PathBuf};
 use std::sync::Arc;
+use std::time::Duration;
 
 use bytes::Bytes;
 use cid::Cid;
@@ -150,6 +152,24 @@ impl Drop for WriterHandle {
     }
 }
 
+#[derive(Clone, Copy, Debug)]
+pub struct OpenRetryPolicy {
+    pub max_attempts: NonZeroU8,
+    pub initial_backoff: Duration,
+    pub max_backoff: Duration,
+}
+
+impl Default for OpenRetryPolicy {
+    fn default() -> Self {
+        const DEFAULT_MAX_ATTEMPTS: NonZeroU8 = NonZeroU8::new(5).unwrap();
+        Self {
+            max_attempts: DEFAULT_MAX_ATTEMPTS,
+            initial_backoff: Duration::from_millis(100),
+            max_backoff: Duration::from_secs(2),
+        }
+    }
+}
+
 impl TranquilBlockStore<RealIO> {
     pub fn open(config: BlockStoreConfig) -> Result<Self, RepoError> {
         Self::open_with_hook(config, None)
@@ -161,6 +181,50 @@ impl TranquilBlockStore<RealIO> {
     ) -> Result<Self, RepoError> {
         Self::open_with_io_hook(config, RealIO::new, post_sync_hook)
     }
+
+    pub fn open_with_retry(
+        config: BlockStoreConfig,
+        policy: OpenRetryPolicy,
+    ) -> Result<Self, RepoError> {
+        retry_with_backoff(policy, &mut |_| Self::open(config.clone()))
+    }
+}
+
+fn retry_with_backoff<T, F>(policy: OpenRetryPolicy, op: &mut F) -> Result<T, RepoError>
+where
+    F: FnMut(u8) -> Result<T, RepoError>,
+{
+    retry_attempt(policy, op, 0, policy.initial_backoff)
+}
+
+fn retry_attempt<T, F>(
+    policy: OpenRetryPolicy,
+    op: &mut F,
+    attempt: u8,
+    backoff: Duration,
+) -> Result<T, RepoError>
+where
+    F: FnMut(u8) -> Result<T, RepoError>,
+{
+    match op(attempt) {
+        Ok(t) => Ok(t),
+        Err(e) if attempt + 1 >= policy.max_attempts.get() => Err(e),
+        Err(e) => {
+            tracing::warn!(
+                attempt,
+                error = %e,
+                backoff_ms = u64::try_from(backoff.as_millis()).unwrap_or(u64::MAX),
+                "blockstore open failed, retrying"
+            );
+            std::thread::sleep(backoff);
+            retry_attempt(
+                policy,
+                op,
+                attempt + 1,
+                (backoff * 2).min(policy.max_backoff),
+            )
+        }
+    }
 }
 
 impl<S: StorageIO + Send + Sync + 'static> TranquilBlockStore<S> {
@@ -331,15 +395,7 @@ impl<S: StorageIO + Send + Sync + 'static> TranquilBlockStore<S> {
         let scan_pos = &mut { start_offset };
         let (scanned_entries, last_valid_end) = std::iter::from_fn(|| {
             match super::data_file::decode_block_record(io, fd, *scan_pos, file_size) {
-                Err(e) => {
-                    tracing::warn!(
-                        file_id = %file_id,
-                        offset = scan_pos.raw(),
-                        error = %e,
-                        "IO error during recovery scan, stopping"
-                    );
-                    None
-                }
+                Err(e) => Some(Err(e)),
                 Ok(None) => None,
                 Ok(Some(ReadBlockRecord::Valid {
                     offset,
@@ -354,7 +410,7 @@ impl<S: StorageIO + Send + Sync + 'static> TranquilBlockStore<S> {
                     let record_size = BLOCK_RECORD_OVERHEAD as u64 + u64::from(raw_len);
                     let new_end = offset.advance(record_size);
                     *scan_pos = new_end;
-                    Some((
+                    Some(Ok((
                         cid_bytes,
                         BlockLocation {
                             file_id,
@@ -362,20 +418,30 @@ impl<S: StorageIO + Send + Sync + 'static> TranquilBlockStore<S> {
                             length,
                         },
                         new_end,
-                    ))
+                    )))
                 }
                 Ok(Some(ReadBlockRecord::Corrupted { .. } | ReadBlockRecord::Truncated { .. })) => {
                     None
                 }
             }
         })
-        .fold(
+        .try_fold(
             (Vec::new(), start_offset),
-            |(mut entries, _), (cid, loc, new_end)| {
+            |(mut entries, _), item: io::Result<_>| {
+                let (cid, loc, new_end) = item?;
                 entries.push((cid, loc));
-                (entries, new_end)
+                Ok::<_, io::Error>((entries, new_end))
             },
-        );
+        )
+        .map_err(|e| {
+            tracing::warn!(
+                file_id = %file_id,
+                offset = scan_pos.raw(),
+                error = %e,
+                "IO error during recovery scan, aborting to preserve durable tail"
+            );
+            RepoError::storage(e)
+        })?;
 
         if file_size > last_valid_end.raw() {
             tracing::info!(
@@ -533,6 +599,16 @@ impl<S: StorageIO + Send + Sync + 'static> TranquilBlockStore<S> {
             .map_err(RepoError::storage)
     }
 
+    pub fn list_hint_files(&self) -> Result<Vec<DataFileId>, RepoError> {
+        let io = self.reader.manager().io();
+        super::list_files_by_extension(io, &self.data_dir, super::hint::HINT_FILE_EXTENSION)
+            .map_err(RepoError::storage)
+    }
+
+    pub fn hint_file_path(&self, file_id: DataFileId) -> std::path::PathBuf {
+        super::hint::hint_file_path(&self.data_dir, file_id)
+    }
+
     pub fn put_blocks_blocking(
         &self,
         blocks: Vec<([u8; CID_SIZE], Vec<u8>)>,
@@ -713,3 +789,210 @@ impl<S: StorageIO + Send + Sync + 'static> TranquilBlockStore<S> {
         Ok(self.index.get(&cid_bytes).map(|entry| entry.refcount.raw()))
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    use std::collections::HashMap;
+    use std::sync::Mutex;
+    use std::sync::atomic::{AtomicBool, Ordering};
+
+    use crate::blockstore::data_file::{
+        BLOCK_FORMAT_VERSION, BLOCK_HEADER_SIZE, BLOCK_MAGIC, encode_block_record,
+    };
+    use crate::blockstore::manager::DATA_FILE_EXTENSION;
+    use crate::io::FileId;
+
+    struct EioOnReadAtRange {
+        inner: RealIO,
+        target_path: PathBuf,
+        target_min: u64,
+        target_max: u64,
+        fired: AtomicBool,
+        fd_paths: Mutex<HashMap<FileId, PathBuf>>,
+    }
+
+    impl StorageIO for EioOnReadAtRange {
+        fn open(&self, path: &Path, opts: OpenOptions) -> io::Result<FileId> {
+            let fd = self.inner.open(path, opts)?;
+            self.fd_paths.lock().unwrap().insert(fd, path.to_path_buf());
+            Ok(fd)
+        }
+
+        fn close(&self, fd: FileId) -> io::Result<()> {
+            self.fd_paths.lock().unwrap().remove(&fd);
+            self.inner.close(fd)
+        }
+
+        fn read_at(&self, fd: FileId, offset: u64, buf: &mut [u8]) -> io::Result<usize> {
+            let path_match = self.fd_paths.lock().unwrap().get(&fd).cloned();
+            let in_target_range = path_match.as_ref() == Some(&self.target_path)
+                && offset >= self.target_min
+                && offset <= self.target_max;
+            if in_target_range && !self.fired.swap(true, Ordering::SeqCst) {
+                return Err(io::Error::other("simulated EIO on read"));
+            }
+            self.inner.read_at(fd, offset, buf)
+        }
+
+        fn write_at(&self, fd: FileId, offset: u64, buf: &[u8]) -> io::Result<usize> {
+            self.inner.write_at(fd, offset, buf)
+        }
+
+        fn sync(&self, fd: FileId) -> io::Result<()> {
+            self.inner.sync(fd)
+        }
+
+        fn file_size(&self, fd: FileId) -> io::Result<u64> {
+            self.inner.file_size(fd)
+        }
+
+        fn truncate(&self, fd: FileId, size: u64) -> io::Result<()> {
+            self.inner.truncate(fd, size)
+        }
+
+        fn rename(&self, from: &Path, to: &Path) -> io::Result<()> {
+            self.inner.rename(from, to)
+        }
+
+        fn delete(&self, path: &Path) -> io::Result<()> {
+            self.inner.delete(path)
+        }
+
+        fn mkdir(&self, path: &Path) -> io::Result<()> {
+            self.inner.mkdir(path)
+        }
+
+        fn sync_dir(&self, path: &Path) -> io::Result<()> {
+            self.inner.sync_dir(path)
+        }
+
+        fn list_dir(&self, path: &Path) -> io::Result<Vec<PathBuf>> {
+            self.inner.list_dir(path)
+        }
+    }
+
+    #[test]
+    fn scan_and_index_does_not_truncate_acked_block_on_transient_eio() {
+        let tmp = tempfile::TempDir::new().unwrap();
+        let data_dir = tmp.path().join("data");
+        let index_dir = tmp.path().join("index");
+        std::fs::create_dir_all(&data_dir).unwrap();
+        std::fs::create_dir_all(&index_dir).unwrap();
+
+        let file_id = DataFileId::new(0);
+        let file_path = data_dir.join(format!("{file_id}.{DATA_FILE_EXTENSION}"));
+
+        let setup = RealIO::new();
+        let fd = setup.open(&file_path, OpenOptions::read_write()).unwrap();
+        let mut header = [0u8; BLOCK_HEADER_SIZE];
+        header[..4].copy_from_slice(&BLOCK_MAGIC);
+        header[4] = BLOCK_FORMAT_VERSION;
+        setup.write_all_at(fd, 0, &header).unwrap();
+
+        let cid_a = [0xAAu8; CID_SIZE];
+        let data_a = vec![1u8; 64];
+        let block_a_offset = BlockOffset::new(BLOCK_HEADER_SIZE as u64);
+        let len_a = encode_block_record(&setup, fd, block_a_offset, &cid_a, &data_a).unwrap();
+
+        let block_b_offset_raw = BLOCK_HEADER_SIZE as u64 + len_a;
+        let block_b_offset = BlockOffset::new(block_b_offset_raw);
+        let cid_b = [0xBBu8; CID_SIZE];
+        let data_b = vec![2u8; 64];
+        let len_b = encode_block_record(&setup, fd, block_b_offset, &cid_b, &data_b).unwrap();
+
+        setup.sync(fd).unwrap();
+        setup.close(fd).unwrap();
+        drop(setup);
+
+        let total_size = block_b_offset_raw + len_b;
+        assert_eq!(std::fs::metadata(&file_path).unwrap().len(), total_size);
+
+        let wrapper = EioOnReadAtRange {
+            inner: RealIO::new(),
+            target_path: file_path.clone(),
+            target_min: block_b_offset_raw,
+            target_max: block_b_offset_raw + (BLOCK_RECORD_OVERHEAD as u64) - 1,
+            fired: AtomicBool::new(false),
+            fd_paths: Mutex::new(HashMap::new()),
+        };
+
+        let index = BlockIndex::open(&index_dir).unwrap();
+
+        let result = TranquilBlockStore::<EioOnReadAtRange>::replay_single_file(
+            &wrapper,
+            &data_dir,
+            &index,
+            file_id,
+            BlockOffset::new(BLOCK_HEADER_SIZE as u64),
+        );
+
+        assert!(
+            result.is_err(),
+            "replay must surface transient EIO instead of silently truncating"
+        );
+
+        let post_size = std::fs::metadata(&file_path).unwrap().len();
+        assert_eq!(
+            post_size, total_size,
+            "scan truncated durable acked block past EIO point: expected {total_size} bytes, got {post_size}"
+        );
+    }
+
+    fn instant_policy(max_attempts: u8) -> OpenRetryPolicy {
+        OpenRetryPolicy {
+            max_attempts: NonZeroU8::new(max_attempts).expect("max_attempts must be nonzero"),
+            initial_backoff: Duration::ZERO,
+            max_backoff: Duration::ZERO,
+        }
+    }
+
+    #[test]
+    fn retry_with_backoff_succeeds_on_first_attempt() {
+        let calls = std::sync::atomic::AtomicUsize::new(0);
+        let result = retry_with_backoff(instant_policy(5), &mut |_| {
+            calls.fetch_add(1, Ordering::Relaxed);
+            Ok::<u8, RepoError>(42)
+        });
+        assert_eq!(result.expect("ok"), 42);
+        assert_eq!(calls.load(Ordering::Relaxed), 1);
+    }
+
+    #[test]
+    fn retry_with_backoff_recovers_after_transient_failures() {
+        let calls = std::sync::atomic::AtomicUsize::new(0);
+        let result = retry_with_backoff(instant_policy(5), &mut |_| {
+            let n = calls.fetch_add(1, Ordering::Relaxed);
+            if n >= 2 {
+                Ok::<u8, RepoError>(7)
+            } else {
+                Err(RepoError::storage(io::Error::other("transient EIO")))
+            }
+        });
+        assert_eq!(result.expect("ok"), 7);
+        assert_eq!(calls.load(Ordering::Relaxed), 3);
+    }
+
+    #[test]
+    fn retry_with_backoff_gives_up_after_max_attempts() {
+        let calls = std::sync::atomic::AtomicUsize::new(0);
+        let result: Result<u8, RepoError> = retry_with_backoff(instant_policy(3), &mut |_| {
+            calls.fetch_add(1, Ordering::Relaxed);
+            Err(RepoError::storage(io::Error::other("permanent EIO")))
+        });
+        assert!(result.is_err(), "expected exhaustion error");
+        assert_eq!(calls.load(Ordering::Relaxed), 3);
+    }
+
+    #[test]
+    fn retry_with_backoff_passes_attempt_index_to_op() {
+        let observed = std::sync::Mutex::new(Vec::<u8>::new());
+        let _result: Result<(), RepoError> =
+            retry_with_backoff(instant_policy(4), &mut |attempt| {
+                observed.lock().unwrap().push(attempt);
+                Err(RepoError::storage(io::Error::other("EIO")))
+            });
+        assert_eq!(*observed.lock().unwrap(), vec![0, 1, 2, 3]);
+    }
+}

crates/tranquil-store/src/blockstore/types.rs

@@ -68,7 +68,8 @@ pub struct CollectionResult {
     pub total_bytes: u64,
 }
 
-pub struct CompactionResult {
+#[derive(Debug)]
+pub struct CompactionStats {
     pub file_id: DataFileId,
     pub old_size: u64,
     pub new_size: u64,
@@ -77,6 +78,24 @@ pub struct CompactionResult {
     pub reclaimed_bytes: u64,
 }
 
+#[derive(Debug)]
+pub enum CompactionResult {
+    Compacted(CompactionStats),
+    Purged {
+        file_id: DataFileId,
+        phantom_blocks: u64,
+    },
+}
+
+impl CompactionResult {
+    pub fn file_id(&self) -> DataFileId {
+        match self {
+            Self::Compacted(stats) => stats.file_id,
+            Self::Purged { file_id, .. } => *file_id,
+        }
+    }
+}
+
 pub struct LivenessInfo {
     pub live_bytes: u64,
     pub total_bytes: u64,

crates/tranquil-store/src/consistency.rs

@@ -28,6 +28,8 @@ pub struct ConsistencyReport {
     pub orphaned_user_repos: Vec<OrphanedUserRepo>,
     pub inconsistent_handles: Vec<InconsistentHandle>,
     pub orphan_data_files: Vec<DataFileId>,
+    pub orphan_hint_files: Vec<DataFileId>,
+    pub missing_indexed_files: Vec<DataFileId>,
     pub deserialization_failures: u64,
     pub eventlog_contiguity: Option<SequenceContiguityResult>,
     pub cursor_ahead_of_eventlog: bool,
@@ -74,6 +76,8 @@ impl ConsistencyReport {
             && self.orphaned_user_repos.is_empty()
             && self.inconsistent_handles.is_empty()
             && self.orphan_data_files.is_empty()
+            && self.orphan_hint_files.is_empty()
+            && self.missing_indexed_files.is_empty()
             && self.deserialization_failures == 0
             && self
                 .eventlog_contiguity
@@ -84,6 +88,8 @@ impl ConsistencyReport {
 
     pub fn has_repairable_issues(&self) -> bool {
         !self.orphan_data_files.is_empty()
+            || !self.orphan_hint_files.is_empty()
+            || !self.missing_indexed_files.is_empty()
     }
 
     pub fn has_unrecoverable_issues(&self) -> bool {
@@ -136,6 +142,20 @@ impl ConsistencyReport {
                 "orphan data files with no index references"
             );
         }
+        if !self.orphan_hint_files.is_empty() {
+            tracing::warn!(
+                count = self.orphan_hint_files.len(),
+                files = ?self.orphan_hint_files,
+                "orphan hint files with no matching data file"
+            );
+        }
+        if !self.missing_indexed_files.is_empty() {
+            tracing::warn!(
+                count = self.missing_indexed_files.len(),
+                files = ?self.missing_indexed_files,
+                "index references data files that are missing on disk"
+            );
+        }
         if self.deserialization_failures > 0 {
             tracing::error!(
                 count = self.deserialization_failures,
@@ -181,13 +201,15 @@ impl fmt::Display for ConsistencyReport {
         write!(
             f,
             "INCONSISTENT: dangling_roots={}, dangling_records={}, orphaned_repos={}, \
-             inconsistent_handles={}, orphan_files={}, deserialize_failures={}, \
-             eventlog_gaps={}, cursor_ahead={}",
+             inconsistent_handles={}, orphan_files={}, orphan_hints={}, missing_indexed_files={}, \
+             deserialize_failures={}, eventlog_gaps={}, cursor_ahead={}",
             self.dangling_root_cids.len(),
             self.dangling_record_cids.len(),
             self.orphaned_user_repos.len(),
             self.inconsistent_handles.len(),
             self.orphan_data_files.len(),
+            self.orphan_hint_files.len(),
+            self.missing_indexed_files.len(),
             self.deserialization_failures,
             self.eventlog_contiguity
                 .as_ref()
@@ -204,6 +226,8 @@ pub struct ConsistencyCheckOptions {
     pub check_user_blocks: bool,
     pub check_eventlog: bool,
     pub check_orphan_files: bool,
+    pub check_missing_indexed_files: bool,
+    pub check_orphan_hint_files: bool,
 }
 
 impl Default for ConsistencyCheckOptions {
@@ -214,6 +238,8 @@ impl Default for ConsistencyCheckOptions {
             check_user_blocks: true,
             check_eventlog: true,
             check_orphan_files: true,
+            check_missing_indexed_files: true,
+            check_orphan_hint_files: true,
         }
     }
 }
@@ -269,6 +295,14 @@ pub fn verify_store_consistency_with_options<S: StorageIO + 'static>(
         check_orphan_data_files(blockstore, block_index, &mut report);
     }
 
+    if options.check_missing_indexed_files {
+        check_missing_indexed_files(blockstore, block_index, &mut report);
+    }
+
+    if options.check_orphan_hint_files {
+        check_orphan_hint_files(blockstore, &mut report);
+    }
+
     report
 }
 
@@ -565,6 +599,52 @@ fn check_orphan_data_files(
     });
 }
 
+fn check_missing_indexed_files(
+    blockstore: &TranquilBlockStore,
+    block_index: &BlockIndex,
+    report: &mut ConsistencyReport,
+) {
+    let disk_files: HashSet<DataFileId> = match blockstore.list_data_files() {
+        Ok(files) => files.into_iter().collect(),
+        Err(e) => {
+            tracing::warn!(error = %e, "failed to list data files for missing-file check");
+            return;
+        }
+    };
+
+    let epoch = blockstore.epoch().current();
+    let now = crate::wall_clock_ms();
+    let indexed_files = block_index.liveness_by_file(epoch, now, 0);
+
+    indexed_files
+        .iter()
+        .filter(|(fid, _)| !disk_files.contains(fid))
+        .for_each(|(fid, _)| report.missing_indexed_files.push(*fid));
+}
+
+fn check_orphan_hint_files(blockstore: &TranquilBlockStore, report: &mut ConsistencyReport) {
+    let data_files: HashSet<DataFileId> = match blockstore.list_data_files() {
+        Ok(files) => files.into_iter().collect(),
+        Err(e) => {
+            tracing::warn!(error = %e, "failed to list data files for orphan-hint check");
+            return;
+        }
+    };
+
+    let hint_files = match blockstore.list_hint_files() {
+        Ok(files) => files,
+        Err(e) => {
+            tracing::warn!(error = %e, "failed to list hint files for orphan-hint check");
+            return;
+        }
+    };
+
+    hint_files
+        .iter()
+        .filter(|fid| !data_files.contains(fid))
+        .for_each(|fid| report.orphan_hint_files.push(*fid));
+}
+
 fn try_cid_bytes_to_fixed(bytes: &[u8]) -> Option<[u8; CID_SIZE]> {
     bytes.try_into().ok()
 }
@@ -621,12 +701,39 @@ pub fn repair_known_issues(
         }
     });
 
+    report.orphan_hint_files.iter().for_each(|&file_id| {
+        let path = blockstore.hint_file_path(file_id);
+        match std::fs::remove_file(&path) {
+            Ok(()) => {
+                tracing::info!(%file_id, "removed orphan hint file");
+                result.orphan_hints_removed = result.orphan_hints_removed.saturating_add(1);
+            }
+            Err(e) => {
+                tracing::warn!(%file_id, error = %e, "failed to remove orphan hint file");
+                result.repair_errors = result.repair_errors.saturating_add(1);
+            }
+        }
+    });
+
+    report.missing_indexed_files.iter().for_each(|&file_id| {
+        let purged = blockstore.block_index().purge_by_file_id(file_id);
+        tracing::info!(
+            %file_id,
+            purged,
+            "purged phantom index entries for missing data file"
+        );
+        result.phantom_index_entries_purged =
+            result.phantom_index_entries_purged.saturating_add(purged);
+    });
+
     result
 }
 
 #[derive(Debug, Default)]
 pub struct RepairResult {
     pub orphan_files_removed: u64,
+    pub orphan_hints_removed: u64,
+    pub phantom_index_entries_purged: u64,
     pub repair_errors: u64,
 }
 

crates/tranquil-store/src/eventlog/writer.rs

@@ -3,16 +3,27 @@ use std::sync::Arc;
 
 use tracing::warn;
 
-use crate::io::StorageIO;
+use crate::io::{FileId, StorageIO};
 
 use super::manager::SegmentManager;
-use super::segment_file::{SEGMENT_HEADER_SIZE, SegmentWriter, ValidEvent};
+use super::segment_file::{
+    SEGMENT_HEADER_SIZE, SEGMENT_MAGIC, SegmentWriter, ValidEvent, ValidateEventRecord,
+    validate_event_record,
+};
 use super::segment_index::{DEFAULT_INDEX_INTERVAL, SegmentIndex, rebuild_from_segment};
 use super::sidecar::build_sidecar_from_segment;
 use super::types::{
     DidHash, EventSequence, EventTypeTag, SegmentId, SegmentOffset, TimestampMicros,
 };
 
+const VALIDATE_RETRY_ATTEMPTS: u32 = 32;
+
+#[derive(Debug, Clone)]
+struct PendingAppend {
+    event: ValidEvent,
+    offset: SegmentOffset,
+}
+
 #[derive(Debug)]
 pub struct SyncResult {
     pub synced_through: EventSequence,
@@ -31,7 +42,8 @@ pub struct EventLogWriter<S: StorageIO> {
     max_payload: u32,
     event_count_in_segment: usize,
     last_event_offset: Option<SegmentOffset>,
-    pending_events: Vec<ValidEvent>,
+    pending: Vec<PendingAppend>,
+    poisoned: bool,
 }
 
 impl<S: StorageIO> EventLogWriter<S> {
@@ -83,10 +95,25 @@ impl<S: StorageIO> EventLogWriter<S> {
             max_payload,
             event_count_in_segment: 0,
             last_event_offset: None,
-            pending_events: Vec::new(),
+            pending: Vec::new(),
+            poisoned: false,
         })
     }
 
+    fn truncate_and_init_fresh(
+        manager: Arc<SegmentManager<S>>,
+        fd: FileId,
+        active_id: SegmentId,
+        prev_segments: &[SegmentId],
+        index_interval: usize,
+        max_payload: u32,
+    ) -> io::Result<Self> {
+        manager.io().truncate(fd, 0)?;
+        let next_seq = find_last_seq_from_segments(&manager, prev_segments, max_payload)?
+            .map_or(EventSequence::new(1), |s| s.next());
+        Self::init_fresh(manager, active_id, next_seq, index_interval, max_payload)
+    }
+
     fn recover_active(
         manager: Arc<SegmentManager<S>>,
         segments: &[SegmentId],
@@ -97,6 +124,19 @@ impl<S: StorageIO> EventLogWriter<S> {
         let handle = manager.open_for_append(active_id)?;
         let fd = handle.fd();
 
+        let prev_segments = &segments[..segments.len().saturating_sub(1)];
+
+        if highest_segment_has_torn_header(manager.io(), fd)? {
+            return Self::truncate_and_init_fresh(
+                Arc::clone(&manager),
+                fd,
+                active_id,
+                prev_segments,
+                index_interval,
+                max_payload,
+            );
+        }
+
         let (index, last_seq_in_active) = match rebuild_from_segment(
             manager.io(),
             fd,
@@ -107,15 +147,11 @@ impl<S: StorageIO> EventLogWriter<S> {
             Err(rebuild_err) => {
                 let file_size = manager.io().file_size(fd)?;
                 if file_size <= SEGMENT_HEADER_SIZE as u64 {
-                    manager.io().truncate(fd, 0)?;
-                    let prev_segments = &segments[..segments.len().saturating_sub(1)];
-                    let next_seq =
-                        find_last_seq_from_segments(&manager, prev_segments, max_payload)?
-                            .map_or(EventSequence::new(1), |s| s.next());
-                    return Self::init_fresh(
+                    return Self::truncate_and_init_fresh(
                         Arc::clone(&manager),
+                        fd,
                         active_id,
-                        next_seq,
+                        prev_segments,
                         index_interval,
                         max_payload,
                     );
@@ -131,8 +167,6 @@ impl<S: StorageIO> EventLogWriter<S> {
 
         let position = SegmentOffset::new(manager.io().file_size(fd)?);
 
-        let prev_segments = &segments[..segments.len().saturating_sub(1)];
-
         let next_seq = match last_seq_in_active {
             Some(seq) => {
                 if let Some(sealed_last) =
@@ -196,7 +230,8 @@ impl<S: StorageIO> EventLogWriter<S> {
             max_payload,
             event_count_in_segment,
             last_event_offset,
-            pending_events: Vec::new(),
+            pending: Vec::new(),
+            poisoned: false,
         })
     }
 
@@ -227,28 +262,20 @@ impl<S: StorageIO> EventLogWriter<S> {
             payload,
         };
 
-        let offset = self.active_writer.append_event(self.manager.io(), &event)?;
-
-        let should_index = self.event_count_in_segment == 0
-            || self
-                .event_count_in_segment
-                .is_multiple_of(self.index_interval);
-        if should_index {
-            self.active_index.record(seq, offset);
-        }
-
-        self.event_count_in_segment = self
-            .event_count_in_segment
-            .checked_add(1)
-            .expect("event_count_in_segment overflow");
-        self.last_event_offset = Some(offset);
-        self.next_seq = seq.next();
-        self.pending_events.push(event);
-
-        Ok(seq)
+        self.append_inner(event).map(|_| seq)
     }
 
     pub fn append_valid_event(&mut self, event: ValidEvent) -> io::Result<()> {
+        self.append_inner(event)
+    }
+
+    fn append_inner(&mut self, event: ValidEvent) -> io::Result<()> {
+        if self.poisoned {
+            return Err(io::Error::other(
+                "writer poisoned by partial-valid sync; reopen required",
+            ));
+        }
+
         let offset = self.active_writer.append_event(self.manager.io(), &event)?;
 
         let should_index = self.event_count_in_segment == 0
@@ -265,21 +292,52 @@ impl<S: StorageIO> EventLogWriter<S> {
             .expect("event_count_in_segment overflow");
         self.last_event_offset = Some(offset);
         self.next_seq = event.seq.next();
-        self.pending_events.push(event);
+        self.pending.push(PendingAppend { event, offset });
 
         Ok(())
     }
 
-    pub fn peek_pending_event(&self, seq: EventSequence) -> Option<&ValidEvent> {
-        self.pending_events.iter().find(|e| e.seq == seq)
-    }
-
     pub fn sync(&mut self) -> io::Result<SyncResult> {
-        if !self.pending_events.is_empty() {
-            self.active_writer.sync(self.manager.io())?;
+        if self.poisoned {
+            return Err(io::Error::other(
+                "writer poisoned by partial-valid sync; reopen required",
+            ));
         }
 
-        let flushed = std::mem::take(&mut self.pending_events);
+        if !self.pending.is_empty() {
+            self.active_writer.sync(self.manager.io())?;
+            self.manager.io().barrier()?;
+        }
+
+        let pending = std::mem::take(&mut self.pending);
+
+        let fd = self.active_writer.fd();
+        let file_size = self.manager.io().file_size(fd)?;
+
+        let valid_count = pending
+            .iter()
+            .take_while(|p| {
+                validate_with_retry(
+                    self.manager.io(),
+                    fd,
+                    p.offset,
+                    file_size,
+                    self.max_payload,
+                    p.event.seq,
+                )
+            })
+            .count();
+
+        if valid_count < pending.len() {
+            self.poisoned = true;
+        }
+
+        let flushed: Vec<ValidEvent> = pending
+            .into_iter()
+            .take(valid_count)
+            .map(|p| p.event)
+            .collect();
+
         self.synced_seq = flushed.last().map(|e| e.seq).unwrap_or(self.synced_seq);
 
         Ok(SyncResult {
@@ -290,12 +348,22 @@ impl<S: StorageIO> EventLogWriter<S> {
         })
     }
 
+    pub fn is_poisoned(&self) -> bool {
+        self.poisoned
+    }
+
     pub fn rotate_if_needed(&mut self) -> io::Result<Option<SegmentId>> {
+        if self.poisoned {
+            return Err(io::Error::other(
+                "writer poisoned by partial-valid sync; reopen required",
+            ));
+        }
+
         if !self.manager.should_rotate(self.active_writer.position()) {
             return Ok(None);
         }
 
-        if !self.pending_events.is_empty() {
+        if !self.pending.is_empty() {
             return Ok(None);
         }
 
@@ -386,6 +454,40 @@ impl<S: StorageIO> EventLogWriter<S> {
     }
 }
 
+fn validate_with_retry<S: StorageIO>(
+    io: &S,
+    fd: FileId,
+    offset: SegmentOffset,
+    file_size: u64,
+    max_payload: u32,
+    expected_seq: EventSequence,
+) -> bool {
+    (0..VALIDATE_RETRY_ATTEMPTS).any(|_| {
+        matches!(
+            validate_event_record(io, fd, offset, file_size, max_payload),
+            Ok(Some(ValidateEventRecord::Valid { seq, .. })) if seq == expected_seq
+        )
+    })
+}
+
+fn highest_segment_has_torn_header<S: StorageIO>(io: &S, fd: FileId) -> io::Result<bool> {
+    let file_size = io.file_size(fd)?;
+    if file_size < SEGMENT_HEADER_SIZE as u64 {
+        return Ok(true);
+    }
+    let outcomes: Vec<bool> = (0..VALIDATE_RETRY_ATTEMPTS)
+        .filter_map(|_| {
+            let mut header = [0u8; SEGMENT_MAGIC.len()];
+            io.read_exact_at(fd, 0, &mut header)
+                .ok()
+                .map(|()| header == SEGMENT_MAGIC)
+        })
+        .collect();
+    let saw_match = outcomes.iter().any(|&ok| ok);
+    let saw_mismatch = outcomes.iter().any(|&ok| !ok);
+    Ok(!saw_match && saw_mismatch)
+}
+
 fn find_last_seq_from_segments<S: StorageIO>(
     manager: &SegmentManager<S>,
     segments: &[SegmentId],
@@ -1094,4 +1196,62 @@ mod tests {
 
         assert!(writer.rotate_if_needed().unwrap().is_none());
     }
+
+    #[test]
+    fn sync_must_not_certify_durability_when_io_sync_silently_drops() {
+        use crate::sim::{FaultConfig, Probability};
+
+        let sim = Arc::new(SimulatedIO::new(
+            0,
+            FaultConfig {
+                sync_failure_probability: Probability::new(1.0),
+                ..FaultConfig::none()
+            },
+        ));
+        sim.set_pristine_mode(true);
+
+        let mgr = Arc::new(
+            SegmentManager::new(Arc::clone(&sim), PathBuf::from("/segments"), 64 * 1024).unwrap(),
+        );
+
+        let mut writer =
+            EventLogWriter::open(Arc::clone(&mgr), DEFAULT_INDEX_INTERVAL, MAX_EVENT_PAYLOAD)
+                .unwrap();
+
+        sim.set_pristine_mode(false);
+
+        writer
+            .append(
+                DidHash::from_did("did:plc:bug2"),
+                EventTypeTag::COMMIT,
+                b"bug2-payload".to_vec(),
+            )
+            .unwrap();
+
+        assert!(
+            writer.sync().is_err(),
+            "sync must surface dropped fsync as an error"
+        );
+        let claimed_synced = writer.synced_seq();
+        assert_eq!(
+            claimed_synced.raw(),
+            0,
+            "synced_seq must not advance past a failed sync"
+        );
+        drop(writer);
+
+        mgr.shutdown();
+        sim.crash();
+        sim.set_pristine_mode(true);
+
+        let reopened =
+            EventLogWriter::open(Arc::clone(&mgr), DEFAULT_INDEX_INTERVAL, MAX_EVENT_PAYLOAD)
+                .unwrap();
+        let actually_durable = reopened.current_seq();
+
+        assert!(
+            actually_durable >= claimed_synced,
+            "writer claimed sync through {claimed_synced} but post-crash recovery only reaches {actually_durable}"
+        );
+    }
 }

crates/tranquil-store/src/gauntlet/chaos_walker.rs

@@ -0,0 +1,113 @@
+use std::collections::HashSet;
+
+use cid::Cid;
+use jacquard_repo::mst::NodeData;
+
+use super::oracle::{hex_short, try_cid_to_fixed};
+use crate::StorageIO;
+use crate::blockstore::{CidBytes, TranquilBlockStore};
+
+pub enum LookupResult {
+    Found(Cid),
+    NotFound,
+    LostPath,
+}
+
+pub fn walk_mst_node_cids_tolerant<S: StorageIO + Send + Sync + 'static>(
+    store: &TranquilBlockStore<S>,
+    root: Cid,
+    lost: &HashSet<CidBytes>,
+) -> Result<Vec<CidBytes>, String> {
+    let mut visited: HashSet<CidBytes> = HashSet::new();
+    let mut to_visit: Vec<Cid> = vec![root];
+    let mut result: Vec<CidBytes> = Vec::new();
+
+    while let Some(cid) = to_visit.pop() {
+        let cid_bytes = try_cid_to_fixed(&cid).map_err(|e| format!("cid format: {e}"))?;
+        if !visited.insert(cid_bytes) {
+            continue;
+        }
+        if lost.contains(&cid_bytes) {
+            continue;
+        }
+        let node = read_node(store, &cid_bytes)?;
+        result.push(cid_bytes);
+        if let Some(left) = node.left {
+            to_visit.push(left);
+        }
+        node.entries
+            .into_iter()
+            .filter_map(|e| e.tree)
+            .for_each(|t| to_visit.push(t));
+    }
+
+    Ok(result)
+}
+
+pub fn mst_get_tolerant<S: StorageIO + Send + Sync + 'static>(
+    store: &TranquilBlockStore<S>,
+    root: Cid,
+    target: &str,
+    lost: &HashSet<CidBytes>,
+) -> Result<LookupResult, String> {
+    let mut cursor = root;
+    loop {
+        let cursor_bytes = try_cid_to_fixed(&cursor).map_err(|e| format!("cid format: {e}"))?;
+        if lost.contains(&cursor_bytes) {
+            return Ok(LookupResult::LostPath);
+        }
+        let node = read_node(store, &cursor_bytes)?;
+        let keys = full_keys(&node)?;
+        let index = keys
+            .iter()
+            .position(|k| k.as_str() >= target)
+            .unwrap_or(keys.len());
+        if index < keys.len() && keys[index] == target {
+            return Ok(LookupResult::Found(node.entries[index].value));
+        }
+        let subtree = match index {
+            0 => node.left,
+            n => node.entries[n - 1].tree,
+        };
+        match subtree {
+            Some(child) => cursor = child,
+            None => return Ok(LookupResult::NotFound),
+        }
+    }
+}
+
+fn read_node<S: StorageIO + Send + Sync + 'static>(
+    store: &TranquilBlockStore<S>,
+    cid_bytes: &CidBytes,
+) -> Result<NodeData, String> {
+    let bytes = match store.get_block_sync(cid_bytes) {
+        Ok(Some(b)) => b,
+        Ok(None) => return Err(format!("missing block: {}", hex_short(cid_bytes))),
+        Err(e) => return Err(format!("read {}: {e}", hex_short(cid_bytes))),
+    };
+    serde_ipld_dagcbor::from_slice(&bytes)
+        .map_err(|e| format!("deserialize node {}: {e}", hex_short(cid_bytes)))
+}
+
+fn full_keys(node: &NodeData) -> Result<Vec<String>, String> {
+    node.entries
+        .iter()
+        .scan(String::new(), |last_key, entry| {
+            let suffix = match std::str::from_utf8(&entry.key_suffix) {
+                Ok(s) => s,
+                Err(e) => return Some(Err(format!("invalid utf-8 in key suffix: {e}"))),
+            };
+            let prefix_len = entry.prefix_len as usize;
+            if prefix_len > last_key.len() {
+                return Some(Err(format!(
+                    "prefix length {} exceeds last key length {}",
+                    prefix_len,
+                    last_key.len()
+                )));
+            }
+            let full = format!("{}{}", &last_key[..prefix_len], suffix);
+            *last_key = full.clone();
+            Some(Ok(full))
+        })
+        .collect()
+}

crates/tranquil-store/src/gauntlet/farm.rs

@@ -1,5 +1,6 @@
 use std::cell::RefCell;
 use std::panic::{AssertUnwindSafe, catch_unwind};
+use std::path::PathBuf;
 use std::time::{Duration, Instant};
 
 use rayon::prelude::*;
@@ -44,6 +45,17 @@ pub fn run_many_timed<F>(
     make_config: F,
     seeds: impl IntoIterator<Item = Seed>,
 ) -> Vec<(GauntletReport, Duration)>
+where
+    F: Fn(Seed) -> GauntletConfig + Sync + Send,
+{
+    run_many_timed_with_scratch_roots(make_config, &[], seeds)
+}
+
+pub fn run_many_timed_with_scratch_roots<F>(
+    make_config: F,
+    scratch_roots: &[PathBuf],
+    seeds: impl IntoIterator<Item = Seed>,
+) -> Vec<(GauntletReport, Duration)>
 where
     F: Fn(Seed) -> GauntletConfig + Sync + Send,
 {
@@ -51,10 +63,14 @@ where
     seeds
         .into_par_iter()
         .map(|s| {
+            let scratch = scratch_for_thread(scratch_roots, rayon::current_thread_index());
             let start = Instant::now();
             let outcome = catch_unwind(AssertUnwindSafe(|| {
                 let cfg = make_config(s);
-                let gauntlet = Gauntlet::new(cfg).expect("build gauntlet");
+                let mut gauntlet = Gauntlet::new(cfg).expect("build gauntlet");
+                if let Some(root) = scratch {
+                    gauntlet = gauntlet.with_scratch_root(root);
+                }
                 with_runtime(|rt| rt.block_on(gauntlet.run()))
             }));
             let report = outcome.unwrap_or_else(|payload| {
@@ -66,6 +82,14 @@ where
         .collect()
 }
 
+fn scratch_for_thread(roots: &[PathBuf], thread_idx: Option<usize>) -> Option<PathBuf> {
+    if roots.is_empty() {
+        None
+    } else {
+        Some(roots[thread_idx.unwrap_or(0) % roots.len()].clone())
+    }
+}
+
 fn panic_report(seed: Seed, payload: Box<dyn std::any::Any + Send>) -> GauntletReport {
     let msg = payload
         .downcast_ref::<&'static str>()
@@ -84,3 +108,59 @@ fn panic_report(seed: Seed, payload: Box<dyn std::any::Any + Send>) -> GauntletR
         ops: OpStream::empty(),
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn scratch_for_thread_returns_none_when_roots_empty() {
+        assert!(scratch_for_thread(&[], Some(0)).is_none());
+        assert!(scratch_for_thread(&[], Some(7)).is_none());
+        assert!(scratch_for_thread(&[], None).is_none());
+    }
+
+    #[test]
+    fn scratch_for_thread_round_robins_across_roots() {
+        let roots = vec![
+            PathBuf::from("/scratch/a"),
+            PathBuf::from("/scratch/b"),
+            PathBuf::from("/scratch/c"),
+        ];
+        let assigned: Vec<PathBuf> = (0..7)
+            .map(|i| scratch_for_thread(&roots, Some(i)).expect("scratch path"))
+            .collect();
+        assert_eq!(
+            assigned,
+            vec![
+                PathBuf::from("/scratch/a"),
+                PathBuf::from("/scratch/b"),
+                PathBuf::from("/scratch/c"),
+                PathBuf::from("/scratch/a"),
+                PathBuf::from("/scratch/b"),
+                PathBuf::from("/scratch/c"),
+                PathBuf::from("/scratch/a"),
+            ]
+        );
+    }
+
+    #[test]
+    fn scratch_for_thread_with_single_root_returns_same_path() {
+        let roots = vec![PathBuf::from("/scratch/only")];
+        (0..5).for_each(|i| {
+            assert_eq!(
+                scratch_for_thread(&roots, Some(i)),
+                Some(PathBuf::from("/scratch/only"))
+            );
+        });
+    }
+
+    #[test]
+    fn scratch_for_thread_falls_back_to_root_zero_outside_pool() {
+        let roots = vec![PathBuf::from("/scratch/a"), PathBuf::from("/scratch/b")];
+        assert_eq!(
+            scratch_for_thread(&roots, None),
+            Some(PathBuf::from("/scratch/a"))
+        );
+    }
+}

crates/tranquil-store/src/gauntlet/flaky.rs

@@ -405,6 +405,8 @@ fn mount_ext4(device: &Path, target: &Path) -> Result<(), FlakyError> {
     let out = Command::new("mount")
         .arg("-t")
         .arg("ext4")
+        .arg("-o")
+        .arg("errors=continue")
         .arg(device)
         .arg(target)
         .output()?;

crates/tranquil-store/src/gauntlet/invariants.rs

@@ -31,6 +31,9 @@ impl InvariantSet {
     pub const MONOTONIC_SEQ: Self = Self(1 << 10);
     pub const FSYNC_ORDERING: Self = Self(1 << 11);
     pub const TOMBSTONE_BOUND: Self = Self(1 << 12);
+    pub const INDEX_BACKED_BY_DISK: Self = Self(1 << 13);
+    pub const HINT_BACKED_BY_DATA: Self = Self(1 << 14);
+    pub const INDEX_BLOCKS_READABLE: Self = Self(1 << 15);
 
     const ALL_KNOWN: u32 = Self::REFCOUNT_CONSERVATION.0
         | Self::REACHABILITY.0
@@ -44,7 +47,10 @@ impl InvariantSet {
         | Self::CHECKSUM_COVERAGE.0
         | Self::MONOTONIC_SEQ.0
         | Self::FSYNC_ORDERING.0
-        | Self::TOMBSTONE_BOUND.0;
+        | Self::TOMBSTONE_BOUND.0
+        | Self::INDEX_BACKED_BY_DISK.0
+        | Self::HINT_BACKED_BY_DATA.0
+        | Self::INDEX_BLOCKS_READABLE.0;
 
     pub const fn contains(self, other: Self) -> bool {
         (self.0 & other.0) == other.0
@@ -377,6 +383,164 @@ fn compact_by_liveness<S: StorageIO + Send + Sync + 'static>(
         })
 }
 
+pub struct HintBackedByData;
+
+#[async_trait]
+impl<S: StorageIO + Send + Sync + 'static> Invariant<S> for HintBackedByData {
+    fn name(&self) -> &'static str {
+        "HintBackedByData"
+    }
+
+    async fn check(&self, ctx: &InvariantCtx<'_, S>) -> Result<(), InvariantViolation> {
+        let store_c = ctx.store.clone();
+        let result = tokio::task::spawn_blocking(move || {
+            let data: std::collections::HashSet<_> = store_c
+                .list_data_files()
+                .map_err(|e| e.to_string())?
+                .into_iter()
+                .collect();
+            let hints = store_c.list_hint_files().map_err(|e| e.to_string())?;
+            let orphans: Vec<String> = hints
+                .iter()
+                .filter(|fid| !data.contains(fid))
+                .map(|fid| fid.to_string())
+                .collect();
+            Ok::<_, String>(orphans)
+        })
+        .await
+        .map_err(|e| InvariantViolation {
+            invariant: "HintBackedByData",
+            detail: format!("join: {e}"),
+        })?;
+
+        let orphans = result.map_err(|e| InvariantViolation {
+            invariant: "HintBackedByData",
+            detail: e,
+        })?;
+
+        if orphans.is_empty() {
+            Ok(())
+        } else {
+            Err(InvariantViolation {
+                invariant: "HintBackedByData",
+                detail: format!(
+                    "hint files without matching data file (orphan hints): {}",
+                    orphans.join(", ")
+                ),
+            })
+        }
+    }
+}
+
+pub struct IndexBlocksReadable;
+
+#[async_trait]
+impl<S: StorageIO + Send + Sync + 'static> Invariant<S> for IndexBlocksReadable {
+    fn name(&self) -> &'static str {
+        "IndexBlocksReadable"
+    }
+
+    async fn check(&self, ctx: &InvariantCtx<'_, S>) -> Result<(), InvariantViolation> {
+        let store_c = ctx.store.clone();
+        let result = tokio::task::spawn_blocking(move || {
+            let entries = store_c.block_index().live_entries_snapshot();
+            let unreadable: Vec<String> = entries
+                .iter()
+                .take(INDEX_READABLE_SAMPLE_CAP)
+                .filter_map(|(cid, _)| match store_c.get_block_sync(cid) {
+                    Ok(Some(_)) => None,
+                    Ok(None) => Some(format!(
+                        "{}: index says present but reader missed",
+                        hex_short(cid)
+                    )),
+                    Err(e) => Some(format!("{}: read error {e}", hex_short(cid))),
+                })
+                .take(INDEX_READABLE_REPORT_CAP)
+                .collect();
+            Ok::<_, String>(unreadable)
+        })
+        .await
+        .map_err(|e| InvariantViolation {
+            invariant: "IndexBlocksReadable",
+            detail: format!("join: {e}"),
+        })?;
+
+        let unreadable = result.map_err(|e| InvariantViolation {
+            invariant: "IndexBlocksReadable",
+            detail: e,
+        })?;
+
+        if unreadable.is_empty() {
+            Ok(())
+        } else {
+            Err(InvariantViolation {
+                invariant: "IndexBlocksReadable",
+                detail: format!(
+                    "live index entries cannot be read back (first {INDEX_READABLE_REPORT_CAP}): {}",
+                    unreadable.join("; ")
+                ),
+            })
+        }
+    }
+}
+
+const INDEX_READABLE_SAMPLE_CAP: usize = 512;
+const INDEX_READABLE_REPORT_CAP: usize = 20;
+
+pub struct IndexBackedByDisk;
+
+#[async_trait]
+impl<S: StorageIO + Send + Sync + 'static> Invariant<S> for IndexBackedByDisk {
+    fn name(&self) -> &'static str {
+        "IndexBackedByDisk"
+    }
+
+    async fn check(&self, ctx: &InvariantCtx<'_, S>) -> Result<(), InvariantViolation> {
+        let store_c = ctx.store.clone();
+        let result = tokio::task::spawn_blocking(move || {
+            let disk: std::collections::HashSet<_> = store_c
+                .list_data_files()
+                .map_err(|e| e.to_string())?
+                .into_iter()
+                .collect();
+            let liveness = store_c.compaction_liveness(0).map_err(|e| e.to_string())?;
+            let missing: Vec<String> = liveness
+                .iter()
+                .filter(|(fid, _)| !disk.contains(fid))
+                .map(|(fid, info)| {
+                    format!(
+                        "{fid} (live_blocks={}, total_blocks={})",
+                        info.live_blocks, info.total_blocks
+                    )
+                })
+                .collect();
+            Ok::<_, String>(missing)
+        })
+        .await
+        .map_err(|e| InvariantViolation {
+            invariant: "IndexBackedByDisk",
+            detail: format!("join: {e}"),
+        })?;
+
+        let missing = result.map_err(|e| InvariantViolation {
+            invariant: "IndexBackedByDisk",
+            detail: e,
+        })?;
+
+        if missing.is_empty() {
+            Ok(())
+        } else {
+            Err(InvariantViolation {
+                invariant: "IndexBackedByDisk",
+                detail: format!(
+                    "index references data files missing on disk (iris-shaped corruption): {}",
+                    missing.join(", ")
+                ),
+            })
+        }
+    }
+}
+
 pub struct NoOrphanFiles;
 
 #[async_trait]
@@ -766,6 +930,18 @@ pub fn invariants_for<S: StorageIO + Send + Sync + 'static>(
             Box::new(CompactionIdempotent),
         ),
         (InvariantSet::NO_ORPHAN_FILES, Box::new(NoOrphanFiles)),
+        (
+            InvariantSet::INDEX_BACKED_BY_DISK,
+            Box::new(IndexBackedByDisk),
+        ),
+        (
+            InvariantSet::HINT_BACKED_BY_DATA,
+            Box::new(HintBackedByData),
+        ),
+        (
+            InvariantSet::INDEX_BLOCKS_READABLE,
+            Box::new(IndexBlocksReadable),
+        ),
         (InvariantSet::BYTE_BUDGET, Box::new(ByteBudget::default())),
         (
             InvariantSet::MANIFEST_EQUALS_REALITY,

crates/tranquil-store/src/gauntlet/mod.rs

@@ -1,3 +1,4 @@
+pub mod chaos_walker;
 pub mod farm;
 pub mod flaky;
 pub mod invariants;
@@ -17,13 +18,14 @@ pub use flaky::{
     BackingMegabytes, DownIntervalSecs, FlakyConfig, FlakyError, FlakyMount, UpIntervalSecs,
 };
 pub use invariants::{
-    EventLogSnapshot, Invariant, InvariantSet, InvariantViolation, SnapshotEvent, invariants_for,
+    EventLogSnapshot, HintBackedByData, IndexBackedByDisk, IndexBlocksReadable, Invariant,
+    InvariantCtx, InvariantSet, InvariantViolation, SnapshotEvent, invariants_for,
 };
 pub use leak::{LeakGateBuildError, LeakGateConfig, LeakViolation, evaluate as evaluate_leak_gate};
 pub use metrics::{MetricName, MetricsSample, sample_harness};
 pub use op::{
-    CollectionName, DidSeed, EventKind, Op, OpStream, PayloadSeed, RecordKey, RetentionSecs, Seed,
-    ValueSeed,
+    CollectionName, DidSeed, EventKind, FileChoice, Op, OpStream, PayloadSeed, RecordKey,
+    RetentionSecs, Seed, ValueSeed,
 };
 pub use oracle::{EventExpectation, Oracle};
 pub use overrides::{ConfigOverrides, GroupCommitOverrides, StoreOverrides};

crates/tranquil-store/src/gauntlet/op.rs

@@ -29,6 +29,9 @@ pub enum EventKind {
     Sync,
 }
 
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
+pub struct FileChoice(pub u32);
+
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub enum Op {
     AddRecord {
@@ -58,6 +61,9 @@ pub enum Op {
     ReadBlock {
         value_seed: ValueSeed,
     },
+    ExternalDeleteDataFile {
+        choice: FileChoice,
+    },
 }
 
 impl Op {

crates/tranquil-store/src/gauntlet/oracle.rs

@@ -1,4 +1,4 @@
-use std::collections::HashMap;
+use std::collections::{HashMap, HashSet};
 
 use cid::Cid;
 
@@ -29,6 +29,7 @@ pub struct Oracle {
     unsynced_events: Vec<EventExpectation>,
     last_synced_seq: Option<EventSequence>,
     last_retention_cutoff_us: Option<u64>,
+    lost_blocks: HashSet<CidBytes>,
 }
 
 impl Oracle {
@@ -93,6 +94,27 @@ impl Oracle {
         self.unsynced_events.push(event);
     }
 
+    pub fn mark_blocks_lost(&mut self, cids: impl IntoIterator<Item = CidBytes>) -> usize {
+        let added: HashSet<CidBytes> = cids.into_iter().collect();
+        let added_count = added.len();
+        self.live
+            .retain(|_, record_cid| !added.contains(record_cid));
+        self.lost_blocks.extend(added);
+        added_count
+    }
+
+    pub fn lost_blocks(&self) -> &HashSet<CidBytes> {
+        &self.lost_blocks
+    }
+
+    pub fn is_block_lost(&self, cid: &CidBytes) -> bool {
+        self.lost_blocks.contains(cid)
+    }
+
+    pub fn has_lost_blocks(&self) -> bool {
+        !self.lost_blocks.is_empty()
+    }
+
     pub fn record_event_sync(&mut self, synced_through: EventSequence) {
         let (promoted, remaining): (Vec<_>, Vec<_>) = self
             .unsynced_events