diff --git a/core/src/main/java/google/registry/tools/GenerateAllocationTokensCommand.java b/core/src/main/java/google/registry/tools/GenerateAllocationTokensCommand.java
index d0c4e673a..631114fc1 100644
--- a/core/src/main/java/google/registry/tools/GenerateAllocationTokensCommand.java
+++ b/core/src/main/java/google/registry/tools/GenerateAllocationTokensCommand.java
@@ -15,6 +15,7 @@
 package google.registry.tools;
 
 import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.collect.ImmutableList.toImmutableList;
 import static com.google.common.collect.ImmutableSet.toImmutableSet;
 import static com.google.common.collect.Sets.difference;
 import static google.registry.model.billing.BillingBase.RenewalPriceBehavior.DEFAULT;
@@ -46,6 +47,9 @@ import google.registry.model.domain.token.AllocationToken;
 import google.registry.model.domain.token.AllocationToken.RegistrationBehavior;
 import google.registry.model.domain.token.AllocationToken.TokenStatus;
 import google.registry.model.domain.token.AllocationToken.TokenType;
+import google.registry.model.registrar.Registrar;
+import google.registry.model.tld.Tld;
+import google.registry.model.tld.Tlds;
 import google.registry.persistence.VKey;
 import google.registry.tools.params.MoneyParameter;
 import google.registry.tools.params.TransitionListParameter.TokenStatusTransitions;
@@ -291,10 +295,12 @@ class GenerateAllocationTokensCommand implements Command {
         !ImmutableList.of("").equals(allowedClientIds),
         "Either omit --allowed_client_ids if all registrars are allowed, or include a"
             + " comma-separated list");
+    verifyAllRegistrarIdsExist(allowedClientIds);
 
     checkArgument(
         !ImmutableList.of("").equals(allowedTlds),
         "Either omit --allowed_tlds if all TLDs are allowed, or include a comma-separated list");
+    verifyAllTldsExist(allowedTlds);
 
     if (ImmutableList.of("").equals(allowedEppActions)) {
       allowedEppActions = ImmutableList.of();
@@ -326,6 +332,34 @@ class GenerateAllocationTokensCommand implements Command {
     }
   }
 
+  static void verifyAllRegistrarIdsExist(@Nullable List<String> allowedClientIds) {
+    // a null/empty list means that all registrars are allowed
+    if (isNullOrEmpty(allowedClientIds)) {
+      return;
+    }
+    ImmutableSet<String> allRegistrarIds =
+        Registrar.loadAllKeysCached().stream()
+            .map(VKey::getKey)
+            .map(Object::toString)
+            .collect(toImmutableSet());
+    ImmutableList<String> badRegistrarIds =
+        allowedClientIds.stream()
+            .filter(id -> !allRegistrarIds.contains(id))
+            .collect(toImmutableList());
+    checkArgument(badRegistrarIds.isEmpty(), "Unknown registrar ID(s) %s", badRegistrarIds);
+  }
+
+  static void verifyAllTldsExist(@Nullable List<String> allowedTlds) {
+    // a null/empty list means that all TLDs are allowed
+    if (isNullOrEmpty(allowedTlds)) {
+      return;
+    }
+    ImmutableSet<String> allTlds = Tlds.getTldsOfType(Tld.TldType.REAL);
+    ImmutableList<String> badTlds =
+        allowedTlds.stream().filter(tld -> !allTlds.contains(tld)).collect(toImmutableList());
+    checkArgument(badTlds.isEmpty(), "Unknown REAL TLD(s) %s", badTlds);
+  }
+
   private void verifyTokenStringsDoNotExist() {
     ImmutableSet<String> existingTokenStrings =
         getExistingTokenStrings(ImmutableSet.copyOf(tokenStrings));
diff --git a/core/src/main/java/google/registry/tools/UpdateAllocationTokensCommand.java b/core/src/main/java/google/registry/tools/UpdateAllocationTokensCommand.java
index 4c9d32a29..b2584f84a 100644
--- a/core/src/main/java/google/registry/tools/UpdateAllocationTokensCommand.java
+++ b/core/src/main/java/google/registry/tools/UpdateAllocationTokensCommand.java
@@ -157,6 +157,9 @@ final class UpdateAllocationTokensCommand extends UpdateOrDeleteAllocationTokens
       endToken = true;
     }
 
+    GenerateAllocationTokensCommand.verifyAllRegistrarIdsExist(allowedClientIds);
+    GenerateAllocationTokensCommand.verifyAllTldsExist(allowedTlds);
+
     tokensToSave =
         tm().transact(
                 () ->
diff --git a/core/src/test/java/google/registry/tools/GenerateAllocationTokensCommandTest.java b/core/src/test/java/google/registry/tools/GenerateAllocationTokensCommandTest.java
index 070f78c00..b5baa101c 100644
--- a/core/src/test/java/google/registry/tools/GenerateAllocationTokensCommandTest.java
+++ b/core/src/test/java/google/registry/tools/GenerateAllocationTokensCommandTest.java
@@ -39,6 +39,7 @@ import google.registry.model.domain.fee.FeeQueryCommandExtensionItem.CommandName
 import google.registry.model.domain.token.AllocationToken;
 import google.registry.model.domain.token.AllocationToken.TokenStatus;
 import google.registry.model.reporting.HistoryEntry.HistoryEntryId;
+import google.registry.testing.DatabaseHelper;
 import google.registry.testing.DeterministicStringGenerator;
 import google.registry.testing.DeterministicStringGenerator.Rule;
 import google.registry.util.StringGenerator.Alphabets;
@@ -56,6 +57,7 @@ class GenerateAllocationTokensCommandTest extends CommandTestCase<GenerateAlloca
 
   @BeforeEach
   void beforeEach() {
+    DatabaseHelper.createTlds("tld", "example");
     command.stringGenerator = new DeterministicStringGenerator(Alphabets.BASE_58);
   }
 
@@ -531,6 +533,26 @@ class GenerateAllocationTokensCommandTest extends CommandTestCase<GenerateAlloca
         .isEqualTo("For DEFAULT_PROMO tokens, must specify --token_status_transitions");
   }
 
+  @Test
+  void testFailure_badTld() {
+    assertThat(
+            assertThrows(
+                IllegalArgumentException.class,
+                () -> runCommand("--number", "10", "--allowed_tlds", "badtld")))
+        .hasMessageThat()
+        .isEqualTo("Unknown REAL TLD(s) [badtld]");
+  }
+
+  @Test
+  void testFailure_badRegistrar() {
+    assertThat(
+            assertThrows(
+                IllegalArgumentException.class,
+                () -> runCommand("--number", "10", "--allowed_client_ids", "badregistrar")))
+        .hasMessageThat()
+        .isEqualTo("Unknown registrar ID(s) [badregistrar]");
+  }
+
   private AllocationToken createToken(
       String token,
       @Nullable HistoryEntryId redemptionHistoryEntryId,
diff --git a/core/src/test/java/google/registry/tools/UpdateAllocationTokensCommandTest.java b/core/src/test/java/google/registry/tools/UpdateAllocationTokensCommandTest.java
index 56b8c8d52..15c69e8a6 100644
--- a/core/src/test/java/google/registry/tools/UpdateAllocationTokensCommandTest.java
+++ b/core/src/test/java/google/registry/tools/UpdateAllocationTokensCommandTest.java
@@ -40,14 +40,21 @@ import google.registry.model.domain.fee.FeeQueryCommandExtensionItem.CommandName
 import google.registry.model.domain.token.AllocationToken;
 import google.registry.model.domain.token.AllocationToken.RegistrationBehavior;
 import google.registry.model.domain.token.AllocationToken.TokenStatus;
+import google.registry.testing.DatabaseHelper;
 import org.joda.money.CurrencyUnit;
 import org.joda.money.Money;
 import org.joda.time.DateTime;
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 /** Unit tests for {@link UpdateAllocationTokensCommand}. */
 class UpdateAllocationTokensCommandTest extends CommandTestCase<UpdateAllocationTokensCommand> {
 
+  @BeforeEach
+  void beforeEach() {
+    DatabaseHelper.createTlds("tld", "example");
+  }
+
   @Test
   void testUpdateTlds_setTlds() throws Exception {
     AllocationToken token =
@@ -64,14 +71,24 @@ class UpdateAllocationTokensCommandTest extends CommandTestCase<UpdateAllocation
     assertThat(reloadResource(token).getAllowedTlds()).isEmpty();
   }
 
+  @Test
+  void testUpdateTlds_badTlds() {
+    persistResource(builderWithPromo().build());
+    assertThat(
+            assertThrows(
+                IllegalArgumentException.class, () -> runCommandForced("--allowed_tlds=badtld")))
+        .hasMessageThat()
+        .isEqualTo("Unknown REAL TLD(s) [badtld]");
+  }
+
   @Test
   void testUpdateClientIds_setClientIds() throws Exception {
     AllocationToken token =
         persistResource(
             builderWithPromo().setAllowedRegistrarIds(ImmutableSet.of("toRemove")).build());
-    runCommandForced("--prefix", "token", "--allowed_client_ids", "clientone,clienttwo");
+    runCommandForced("--prefix", "token", "--allowed_client_ids", "TheRegistrar,NewRegistrar");
     assertThat(reloadResource(token).getAllowedRegistrarIds())
-        .containsExactly("clientone", "clienttwo");
+        .containsExactly("TheRegistrar", "NewRegistrar");
   }
 
   @Test
@@ -83,6 +100,17 @@ class UpdateAllocationTokensCommandTest extends CommandTestCase<UpdateAllocation
     assertThat(reloadResource(token).getAllowedRegistrarIds()).isEmpty();
   }
 
+  @Test
+  void testUpdateClientIds_badClientId() {
+    persistResource(builderWithPromo().build());
+    assertThat(
+            assertThrows(
+                IllegalArgumentException.class,
+                () -> runCommandForced("--allowed_client_ids=badregistrar")))
+        .hasMessageThat()
+        .isEqualTo("Unknown registrar ID(s) [badregistrar]");
+  }
+
   @Test
   void testUpdateEppActions_setEppActions() throws Exception {
     AllocationToken token =