Describe the bug
The Google Generative AI API is returning a 400 INVALID_ARGUMENT error when making tool calls with Gemini models, specifically citing a missing thought_signature in the functionCall parts.
Error Message
{
"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:exec , position 75. Please refer to https://ai.google.dev/gemini-api/docs/thought-signatures for more details.",
"status": "INVALID_ARGUMENT"
}
}Context
- Model: Primarily observed with
google/gemini-3.1-pro-preview, but likely affects other Gemini models.
- Action: This error occurs consistently during tool calls (e.g.,
exec).
- Environment: A clean, recent installation of OpenClaw.
Additional Information
A search of existing issues reveals this is a recurring problem with a long history (e.g., #71725, #63397, #58235, #34008). While many related issues are closed, the bug appears to have resurfaced or persists in certain configurations.
Previous attempts to live-patch compiled OpenClaw JavaScript files have been made in the past, but these are brittle workarounds that do not survive reinstalls. The issue seems more persistent with stricter models like Gemini Pro compared to Gemini Flash.
Describe the bug
The Google Generative AI API is returning a 400
INVALID_ARGUMENTerror when making tool calls with Gemini models, specifically citing a missingthought_signaturein thefunctionCallparts.Error Message
{ "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:exec , position 75. Please refer to https://ai.google.dev/gemini-api/docs/thought-signatures for more details.", "status": "INVALID_ARGUMENT" } }Context
google/gemini-3.1-pro-preview, but likely affects other Gemini models.exec).Additional Information
A search of existing issues reveals this is a recurring problem with a long history (e.g., #71725, #63397, #58235, #34008). While many related issues are closed, the bug appears to have resurfaced or persists in certain configurations.
Previous attempts to live-patch compiled OpenClaw JavaScript files have been made in the past, but these are brittle workarounds that do not survive reinstalls. The issue seems more persistent with stricter models like Gemini Pro compared to Gemini Flash.