Repository navigation
[BUG] Native gemini 3-pro tool calls seem to be broken (Function call is missing a thought_signature in functionCall parts) #9499
Description
Problem (one or two sentences)
While trying to use the new native gemini-3-pro tool calls with the gemini provider it seems to have problems with this error being returned:
Gemini generate context stream error: {"error":{"message":"{\n "error": {\n "code": 400,\n "message": "Function call is missing a thought_signature in functionCall parts. This is required for tools to work correctly, and missing thought_signature may lead to degraded model performance. Additional data, function call default_api:ask_followup_question , position 4. Please refer to https://ai.google.dev/gemini-api/docs/thought-signatures for more details.",\n "status": "INVALID_ARGUMENT"\n }\n}\n","code":400,"status":"Bad Request"}}
I've also experienced this with the code search tool.
XML based(non native) tool calls work.
Context (who is affected and when)
Gemini 3.0-pro users that want to use native tool calls with the gemini provider.
Reproduction steps
- Set up gemini-3-pro with the gemini provider.
- Try to push the agent to do tool calls.
Expected result
Tool calls should consistently work.
Actual result
Tool calls inconsistently work.
Variations tried (optional)
No response
App Version
3.34.0
API Provider (optional)
Google Gemini
Model Used (optional)
Gemini-3-pro-preview
Roo Code Task Links (optional)
No response
Activity
[-][BUG] Native gemini 3-pro calls seem to be broken (Function call is missing a thought_signature in functionCall parts)[/-][+][BUG] Native gemini 3-pro tool calls seem to be broken (Function call is missing a thought_signature in functionCall parts)[/+]dmarkey commentedon Nov 22, 2025
You're right, it doesn't seem to happen when I've "Model Reasoning Effort" set.
fix: include thought signatures for gemini-3-pro native tool calls
steenlarsen commentedon Dec 26, 2025
I have the same problem with gemini-3-flash-preview on OpenRouter
Date/time: 2025-12-23T14:41:34.649Z
Extension version: 3.37.0
Provider: openrouter
Model: google/gemini-3-flash-preview
400
OpenRouter completion error: Gemini models require OpenRouter reasoning details to be preserved in each request. Please refer to our docs: https://openrouter.ai/docs/guides/best-practices/reasoning-tokens#preserving-reasoning-blocks. Upstream error: {
"error": {
"code": 400,
"message": "Function call is missing a thought_signature in functionCall parts. This is required for tools to work correctly, and missing thought_signature may lead to degraded model performance. Additional data, function call
default_api:ask_followup_question, position 2. Please refer to https://ai.google.dev/gemini-api/docs/thought-signatures for more details.","status": "INVALID_ARGUMENT"
}
}