Image Studio: ship function_calling=default — Native leaks Qwen 3.5 XML

Qwen 3.5 abliterated emits its native tool-call format
(<function=...><parameter=...>) wrapped in <tool_call> tags that the
current Open WebUI / Ollama parser does not reliably round-trip — the
XML leaks to chat as plain text instead of executing. Switching the
preset to Function Calling: Default, which uses Open WebUI's own
prompt-injection wrapper, fires the tool reliably.

Native is documented as the right choice only when the operator has
swapped the base model to one with proven OWUI-side parser support
(mistral-nemo:12b, qwen2.5vl:7b). For the shipped Qwen 3.5
abliterated default, Default is the working setting.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

deployments/ai-stack/openwebui-models/image_studio.md

@@ -47,7 +47,7 @@ In the **Advanced Params** section:
 
 | Field | Value |
 | ----- | ----- |
-| Function Calling | `Native` (mandatory) |
+| Function Calling | `Default` — `Native` leaks Qwen 3.5's tool-call XML to chat as text instead of executing it. `Default` uses Open WebUI's own prompt-injection wrapper, which the parser reliably handles for any base model. Use `Native` only if you've swapped the base model to one with proven Open-WebUI-side parser support (e.g. `mistral-nemo:12b`). |
 | Temperature | `0.5` (lower = more reliable tool-calling) |
 | Top P | `0.9` |
 | Context Length | leave default |
@@ -207,9 +207,14 @@ the background to a sunset") that doesn't matter.
 - **The system prompt is unambiguous.** No room for the model to
   decide "I'll just describe it in text instead."
 - **Only one tool is attached.** No competing tools to choose between.
-- **Native function calling is mandatory.** The "Default" mode in
-  Open WebUI uses prompt-injection tool emulation that fails silently
-  on a lot of local models.
+- **Function Calling: Default** is the safer choice for Qwen 3.x
+  abliterated. Native mode expects the parser to recognise the
+  model's structured tool-call format, which currently leaks Qwen
+  3.5's `<function=...><parameter=...>` XML to chat as plain text on
+  the published Open WebUI / Ollama versions. Default mode uses Open
+  WebUI's own prompt-injection wrapper that round-trips reliably.
+  Try Native only after swapping the base model to one known to work
+  end-to-end (mistral-nemo, qwen2.5vl).
 - **Lower temperature.** Tool calling is more reliable with less
   sampling randomness.