Generalise OllamaProvider._extract_text_tool_calls to recover a tool-call
JSON object regardless of how a small/quantized model wraps it — qwen's
<tool_call> tags, bare JSON, ```json fences, alternate tags (<tools>,
<function_call>), OpenAI {"function":{…}} nesting, and parameters-vs-arguments.
A new _coerce_call gates recovery on the known tool-name set from the tools
schema, so a stray JSON blob in prose (or a hallucinated make_dir) can never
be coerced into an action. 11-case unit check: 8 leak shapes recover, 3
negatives (prose / unknown tool / random config JSON) ignored.
Benchmark verdict (honest): this does NOT move the weak-CPU-model pass rate
— 3b went 2/1/0 of 12 across three passes (baseline 1/12, noise), 0.5b went
0/0 (baseline 1/12). A direct /api/chat probe shows the hypothesis was wrong
about the FORM of the leak: the weak models emit either malformed structured
tool_calls (write_file content:null) or a fenced bash block in prose with no
tool call at all — not JSON-as-text. The structured-JSON recovery is still a
correct, safe hardening for any model that does leak JSON; the real
weak-model lever (parse ```bash fences -> run_shell) is documented as an
explicit safety decision, not folded in here.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
leetcrypt
92c0a07d56
