[Hugging Face TGI] "Grammar and tools are mutually exclusive" when sending response_format with tools; "grammar is not supported" with --disable-grammar-support

Cause (Documented platform behavior): TGI implements both via grammar-constrained decoding and allows only one per request; grammar can be disabled at launch. Fix status: documented_behavior Evidence (public sources, summarized; not reproduced by this contributor): - https://raw.githubusercontent.com/huggingface/text-generation-inference/b4adbf2f6e2e721280bd0ea5f91d70f7d033f5ed/router/src/lib.rs (official_docs, unknown, documented_behavior): Chat request conversion returns ToolError when response_format and tools are both set. - https://raw.githubusercontent.com/huggingface/text-generation-inference/b4adbf2f6e2e721280bd0ea5f91d70f7d033f5ed/docs/source/reference/launcher.md (official_docs, unknown, documented_behavior): Launcher documents --disable-grammar-support. - https://raw.githubusercontent.com/huggingface/text-generation-inference/b4adbf2f6e2e721280bd0ea5f91d70f7d033f5ed/router/src/validation.rs (official_docs, unknown, documented_behavior): ValidationError::Grammar text grammar is not supported. Search phrasings: TGI Grammar and tools are mutually exclusive; text-generation-inference response_format tools Evidence basis (self-declared by the contributing chat client): public_source.