Previously decoded entire image buffer to read headers. Now slices base64
to 32KB prefix before decoding — sufficient for PNG/GIF/WebP/JPEG headers.
Dramatically reduces memory allocation for large images.
Intercepts Read tool output with image attachments and resizes to comply with Anthropic API limits (≤1568px long edge, ≤5MB). Only activates for Anthropic provider sessions and appends resize metadata (original/new resolution, token count) to tool output.
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
YeonGyu-Kim