Cline error
Cline: Function call is missing a thought_signature in functionCall parts
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.Status: Fixed in releaseLast verified 3 documented fixes4 sources
What it means
Gemini 3 models reject (HTTP 400 INVALID_ARGUMENT) function calls whose thought signatures were not preserved across multi-step tool execution.
Causes
- Gemini 3 Pro makes thought signatures mandatory for function calls and requires all signatures to be preserved across turns (maintainer ClineXDiego).
- Signature handling on the OpenRouter / Cline provider / OpenAI-compatible path differs from the direct Gemini provider path.
How to fix it
- Fix 1.
Update Cline. Maintainers closed #7974 stating the thought_signature issue for the direct Gemini provider was fixed (thought signature support PR #7536, fix PR #8122), and asked anyone still affected on the latest version (3.77.0 at the time) to open a new issue.
- Fix 2.
Workaround from the maintainer thread: use Gemini 3 through the Google Gemini provider with your own API key instead of OpenRouter or the Cline provider.
- Fix 3.
If using Gemini through OpenRouter, signature handling depends on OpenRouter's implementation; check OpenRouter's docs on reasoning token preservation.
More Cline errors
All 17 Cline errorsShell Integration Unavailable. Cline may have trouble viewing the command's output. Please update VSCode (CMD/CTRL + Shift + P → "Update") and make sure you're using a supported shell: zsh, bash, fish, or PowerShell (CMD/CTRL + Shift + P → "Terminal: Select Default Profile").Status: WorkaroundError executing command: The command ran successfully, but we couldn't capture its output. Please proceed accordingly.Status: Fixed in releaseCommand failed with exit code 1: powershell (Get-CimInstance -ClassName Win32_OperatingSystem).caption 'powershell' is not recognized as an internal or external command, operable program or batch file.Status: WorkaroundUnexpected API Response: The language model did not provide any assistant messages. This may indicate an issue with the API or the model's output.Status: WorkaroundInvalid API Response: The provider returned an empty or unparsable response. This is a provider-side issue where the model failed to generate valid output or returned tool calls that Cline cannot process. Retrying the request may help resolve this issue.Status: OpenModel returned empty responseStatus: Open429 {"type":"error","error":{"type":"rate_limit_error","message":"Number of request tokens has exceeded your per-minute rate limit (https://docs.anthropic.com/en/api/rate-limits); see the response headers for current usage. Please reduce the prompt length or the maximum tokens requested, or try again later. You may also contact sales at https://www.anthropic.com/contact-sales to discuss your options for a rate limit increase."}}Status: WorkaroundInvalid MCP settings format. Please ensure your settings follow the correct JSON format.Status: Workaround
Related reading
- What Is Cline? The Open-Source AI Coding Agent for VS CodeCline is a free, open-source VS Code extension for agentic AI coding. Bring your own model, a cloud API or a local one via Ollama, with no vendor lock-in.
- Every AI Coding Tool Compared: The 2026 MatrixEvery AI coding tool compared: 15 terminal, IDE, cloud and browser tools side by side on pricing, model surface, strengths, weaknesses and best use cases.
FAQ
What does "Function call is missing a thought_signature in functionCall parts" mean in Cline?
Gemini 3 models reject (HTTP 400 INVALID_ARGUMENT) function calls whose thought signatures were not preserved across multi-step tool execution.
How do I fix "Function call is missing a thought_signature in functionCall parts"?
There are 3 documented fixes. Start with the first: Update Cline. Maintainers closed #7974 stating the thought_signature issue for the direct Gemini provider was fixed (thought signature support PR #7536, fix PR #8122), and asked anyone still affected on the latest version (3.77.0 at the time) to open a new issue.
Is this Cline error fixed?
Status: Fixed in release. A release fixed this. The affected versions note says where the fix landed. Affected versions: Reported on 3.40.1; fixed for direct Gemini provider by 3.77.0
Sources
Last verified against 4 sources: official docs, maintainer replies and release notes.
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