When using non-Anthropic models on Bedrock (like Amazon Nova or Mistral), the upstream pi-ai provider injects cachePoint blocks into message content by default. These models don't support the Anthropic-specific cache point extension and reject requests with 'extraneous key [cachePoint] is not permitted'.

This passes cacheRetention: "none" to the pi-ai stream options for non-Anthropic Bedrock models, which prevents cachePoint blocks from being added in the first place. Anthropic models on Bedrock are unaffected and keep their existing caching behavior.

Fixes #20815

Greptile Summary

Fixes Bedrock API errors when using non-Anthropic models (Amazon Nova, Mistral) by disabling prompt caching for them. The pi-ai Bedrock provider injects cachePoint blocks by default, but only Claude models support this Anthropic-specific extension.

The fix adds a detection function to identify Claude model IDs (matching anthropic.claude or anthropic/claude) and wraps the stream function to pass cacheRetention: "none" for all other Bedrock models. This prevents the upstream provider from injecting unsupported cache control metadata that would cause API rejection errors.

Confidence Score: 5/5

• This PR is safe to merge with minimal risk
• The fix is narrowly scoped, well-documented, and follows existing patterns in the codebase. The detection logic correctly identifies Anthropic models using case-insensitive string matching, and the wrapper correctly chains with existing streamFn wrappers. No tests need updating since this is defensive behavior that prevents errors rather than changing existing functionality.
• No files require special attention

_{Last reviewed commit: 2302126}