fix: resolve Mistral API compatibility issues#2440
Merged
rekram1-node merged 10 commits intoanomalyco:devfrom Nov 6, 2025
Merged
fix: resolve Mistral API compatibility issues#2440rekram1-node merged 10 commits intoanomalyco:devfrom
rekram1-node merged 10 commits intoanomalyco:devfrom
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Fixes "Unexpected role 'user' after role 'tool'" error that occurs when switching from Claude to Mistral models mid-conversation. Mistral has stricter message sequence requirements than other providers. - Add fixMistralMessageSequence() function to detect tool→user sequences - Insert intermediate assistant messages to maintain proper conversation flow - Apply fix for models containing "mistral" or "devstral" in their name - Preserve valid sequences unchanged Resolves issue where users get API errors when switching between providers during conversations with tool usage.
Resolves 'Unsupported content type in assistant message: undefined' error by ensuring the inserted assistant message has the proper structure expected by the AI SDK.
Mistral API requires tool call IDs to be alphanumeric with exactly 9 characters. Convert IDs like 'toolu_01CBhTTz95qkd9LJMdC9sf8t' to 'toolu01CB'. Fixes 'Tool call id was toolu_01CBhTTz95qkd9LJMdC9sf8t but must be a-z, A-Z, 0-9, with a length of 9' error.
Filter on providerID rather than individual model names to ensure all Mistral models receive the necessary API compatibility transforms, including future model variants.
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I don't want to be that guy but can we please get this in? I really want to use mistral instead of copilot with gtp4.1 but I am facing too many issues with it. What is the blocker here? |
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This was referenced Nov 2, 2025
Tool Call ID Format Incompatible with Mistral API: "must be a-z, A-Z, 0-9, with a length of 9"
#1680
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ill check this out tmr, sorry for delays |
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thank u! |
thdxr
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Nov 7, 2025
Co-authored-by: Aiden Cline <aidenpcline@gmail.com>
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This was referenced Mar 8, 2026
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Summary
Fixes multiple Mistral API compatibility issues that occur when using Mistral models with tool calling:
AI_APICallError: Unexpected role 'user' after role 'tool'by inserting assistant messages between tool and user messages to maintain proper conversation flowError: Unsupported content type in assistant message: undefinedby ensuring inserted messages have proper AI SDK structureRoot Cause
Mistral API requirements:
toolInvocationsfieldSolution
Added Mistral-specific transforms in
packages/opencode/src/provider/transform.ts:normalizeMistralToolCallIds()- converts tool call IDs to 9-character alphanumeric formatfixMistralMessageSequence()- inserts assistant messages to maintain proper sequenceTest Plan
Files Changed
packages/opencode/src/provider/transform.ts- Added Mistral-specific message transformsResolves API errors that occur when using Mistral models with tool calling functionality.
closes #526
closes #1680
closes #2865