Fix tool message content format for DeepSeek API compatibility#99
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mattt merged 2 commits intomattt:mainfrom Feb 4, 2026
Merged
Fix tool message content format for DeepSeek API compatibility#99mattt merged 2 commits intomattt:mainfrom
mattt merged 2 commits intomattt:mainfrom
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DeepSeek API expects tool message content to be a string, not an array. Changed from .blocks() to .text() for tool messages. Also ensures structured tool outputs (JSON) are correctly serialized to JSON strings instead of using debug descriptions.
Drop image segments rather than emitting <image>
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Pull request overview
This PR updates the OpenAI language model implementation to serialize tool message content as strings instead of block arrays, ensuring compatibility with strict OpenAI-compatible APIs like DeepSeek that require tool message content to be a string per the OpenAI API specification.
Changes:
- Introduced
convertSegmentsToToolContentString()function to serialize transcript segments as plain strings for tool messages - Updated all three locations where tool messages are created to use
.text()with string content instead of.blocks()with array content - Text and structured segments are converted to string format, while image segments are omitted from tool message content
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@ajason Thank you for opening this PR! I made a couple changes (most notably, omitting image segments instead of emitting |
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This PR updates the serialization of
toolmessage content to comply with the OpenAI API specification (which requirescontentto be a string) and ensures compatibility with DeepSeek API (https://api-docs.deepseek.com/api/create-chat-completion content of a tool message must be a string ).Changes
toolmessage content from.blocks([...])(array) to.text(...)(string).StructuredSegment(JSON):ImageSegmentis converted to a placeholder string"<image>"as binary/image content cannot be represented in a plain string tool response.Impact
This fixes allows the library to work correctly with strict OpenAI-compatible APIs like DeepSeek.