Fix Qwen session tool calls and expose thinking compatibility

2026-09-21 16:23:51 +02:00
parent efd7d788d9
commit 84084bba37
10 changed files with 220 additions and 4 deletions
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+# Qwen 3.6: session tool-call failure and correction
+
+Date: 2026-09-21. Verified runtime: Pi coding agent and Pi AI 0.80.3.
+
+## Cause and correction
+
+Interactive sessions returned text resembling a bash call and stopped before the
+first review widget. The Evidence-only extension `tht-evidence-json-mode.ts` lived
+under `.pi/extensions`, so Pi automatically loaded it into interactive sessions.
+Its `before_provider_request` hook imposed `response_format: {type: "json_object"}`
+and temperature zero on every request.
+
+Replaying the captured startup request, with all original hooks preserved, isolated
+the cause. With JSON response format, Qwen returned the command as text and finish
+reason `stop`. Removing only that field produced a native `bash` call and finish
+reason `tool_calls`. Both requests contained the same 15 tools and used High thinking.
+
+The extension now lives in `.pi/evidence-extensions` and is loaded explicitly by
+`PiEvidenceRestructurer`. Evidence retains JSON output. Interactive sessions retain
+native tool calls. No changes to the remote Qwen server were required.
+
+Earlier SDK probes replaced `session.agent.onPayload`, inadvertently bypassing the
+extension hooks. Their success did not reproduce the application path and did not
+establish a model or server fault.
+
+## Model configuration
+
+The installation catalog now accepts optional `session.compatibility.thinkingFormat`
+values `qwen` and `qwen-chat-template`, requiring `reasoning: true`. Go validation,
+the backend schema, and generated catalog/Pi projections preserve this setting.
+It controls thinking; it was not the cause or correction of the tool-call failure.
+
+For the verified endpoint, `qwen-chat-template` sends `enable_thinking` and
+`preserve_thinking` inside `chat_template_kwargs`. Selecting Off explicitly disables
+thinking. Declaring `reasoning: false` alone does not disable thinking on the server.
+See the [operator configuration](../general/pi-configuration.md#qwen-36-sessions-and-thinking-controls)
+and [Pi 0.80.3 model documentation](https://github.com/earendil-works/pi/blob/v0.80.3/packages/coding-agent/docs/models.md#openai-compatibility).
+
+## Validation and local delivery
+
+- Catalog and projection regression tests failed before the compatibility change,
+  then passed. Go config/modelprojection/CLI tests, 84 targeted backend tests,
+  TypeScript checking, and the strict documentation build passed.
+- The extension-isolation regression failed before relocation. All 46 Evidence
+  authoring/restructurer tests and Ruff checks on changed Python files passed.
+- The rebuilt local core image has digest
+  `sha256:9cd593d7362dcbefe177f1b9eb4b9ffdf3010ced7bd7efc8fc3fdcd288f24579`.
+  Core/frontend were recreated, healthy, and returned HTTP 200.
+- A real `pi --mode rpc --no-session` probe with Qwen and High thinking executed
+  `tht session show` successfully and reached the first clarification widget.
+  The probe allowed only that read and `reviewer_select`; it stopped without
+  submitting a human response or recording decisions. Its temporary configuration
+  referenced the mounted credential because the original runtime lease had expired.
+- The user subsequently confirmed that the application now works.
+
+This verifies recovery from the startup failure. It does not certify every workflow
+phase or the separate LiteLLM metadata-generation path.