Support model-specific function description prefixes

[copyberry]

Support model-specific function description prefixes

What changed

Add functions_namespace_functions_description_prefixes to model tool messages, keyed by unqualified tool name. Prepend this guidance to descriptions in the functions namespace across direct declarations, Code Mode documentation, and tool-search results, including custom tools.

Trim prefixes, ignore empty values and unavailable functions, and enforce a combined 256-byte UTF-8 limit including separators for reachable tools. Keep overrides local to each step, preserve search ranking text, and retain runtime caches for unaffected tools.

Testing

Extend coverage for direct and indirect descriptions, clearing prefixes when switching models, namespace scoping for deferred dynamic tools, and tool-search cache reuse and reset.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	🔄 Running since 2026-10-08T03:21:04.900957Z	3740a55	PR opened

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