- Add OpenAI-compat executor-time normalization for `tool` message content, converting non-string tool results to plain text and replacing image parts with a clear unsupported marker for models configured with text-only `input-modalities`.
- Apply normalization in both regular and streaming OpenAI-compat execution paths before prompt-cache processing.
- Update config example to document `[text]` `input-modalities` for upstreams that reject multimodal tool-result content.
Closes: #4737
13435c93d2