Anthropic enforces two independent ceilings per image:
1. 5 MB encoded byte size
2. 8000 px longest side
Hermes only guarded #1. A tall screenshot (e.g. 1200x12000 at 0.06 MB)
passes every byte check but fails the pixel check, returning a
non-retryable HTTP 400 that permanently bricks the conversation thread.
Fixes:
- error_classifier: add 'image dimensions exceed' pattern to
_IMAGE_TOO_LARGE_PATTERNS so the 400 is classified as image_too_large
and triggers the shrink/retry path instead of falling through to
non-retryable error.
- conversation_compression: check pixel dimensions (via Pillow) even
when byte size is under the 4 MB target. If max(dims) > 8000, force
shrink.
- vision_tools._resize_image_for_vision: add optional max_dimension param.
When set, images exceeding the pixel cap are downscaled even if they're
under the byte budget. The resize loop now checks both byte AND pixel
limits before accepting a candidate.
Closes#37677
6bdbe30763