OpenRouter normalises to OpenAI's chat schema and inherits the 4-entry stop cap. The default 16-cap was too permissive; add stop_max=4 on both the backend provider registry and the frontend PROVIDER_STOP_MAX map.
The GGUF tool-iteration final-answer pass at llama_cpp.py:5182 was carrying only the legacy sampling fields. Forward frequency_penalty, seed, and parallel_tool_calls there too so the cap-exhausted path matches the per-iteration loop.
Test pins the OpenRouter 4-cap.
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