fix(anthropic): serialize ToolResultContent::Image with source wrapper#1772
Merged
gold-silver-copper merged 1 commit intoMay 16, 2026
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The Anthropic API expects tool result image content in the format:
{"type": "image", "source": {"type": "base64", ...}}
Previously, ToolResultContent::Image was a tuple variant wrapping
ImageSource directly. With #[serde(tag = "type")] internal tagging,
this flattened ImageSource's fields (including its own "type" field)
into the parent object, producing {"type": "base64", ...} which
Anthropic rejects with:
Input tag 'base64' found using 'type' does not match any of the
expected tags: 'document', 'image', 'search_result', 'text',
'tool_reference'
Changed to a struct variant with a "source" field, matching the
pattern already used by Content::Image.
Contributor
|
awesome work ty! |
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Description
Fixes incorrect serialization of
ToolResultContent::Imagewhen sending tool results containing images to the Anthropic API. Any tool that returns image content (screenshots, image generation, etc.) was broken.Fixes #1771
Type of change
Testing
rig-core 0.37.0→ 400 Bad Request with error:Input tag 'base64' found using 'type' does not match any of the expected tagsChecklist:
Notes
The fix changes
ToolResultContent::Imagefrom a tuple variant to a struct variant with asourcefield:This is technically a breaking change to the Anthropic-specific type API (anyone pattern-matching on
ToolResultContent::Image(source)needs to change toToolResultContent::Image { source }), but since the previous serialization was completely non-functional with the Anthropic API, no one could have been using it successfully.