gemini-cli - 💡(How to fix) Fix ✕ [API Error: [{ "error": { "code": 400, "message": "The GenerateContentRequest proto is invalid:\n * tools[0].function_declarations: [FIELD_INVALID] At most 512 function declarations can be specified.", "errors": [ { "message": "The GenerateContentRequest [1 comments, 2 participants]

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google-gemini/gemini-cli#25440Fetched 2026-04-16 07:06:29
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Error Message

✕ [API Error: [{ "error": { "code": 400, "message": "The GenerateContentRequest proto is invalid:\n * tools[0].function_declarations: [FIELD_INVALID] At most 512 function declarations can be specified.", "errors": [ { "message": "The GenerateContentRequest proto is invalid:\n * tools[0].function_declarations: [FIELD_INVALID] At most 512 function declarations can be specified.", "domain": "global", "reason": "badRequest" } ], "status": "INVALID_ARGUMENT" } } ]] I open the terminal in one of my client folders and as soon as I want to write something, I get this error.

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What happened?

✕ [API Error: [{ "error": { "code": 400, "message": "The GenerateContentRequest proto is invalid:\n * tools[0].function_declarations: [FIELD_INVALID] At most 512 function declarations can be specified.", "errors": [ { "message": "The GenerateContentRequest proto is invalid:\n * tools[0].function_declarations: [FIELD_INVALID] At most 512 function declarations can be specified.", "domain": "global", "reason": "badRequest" } ], "status": "INVALID_ARGUMENT" } } ]]

[ACTION REQUIRED] 📎 PLEASE ATTACH THE EXPORTED CHAT HISTORY JSON FILE TO THIS ISSUE IF YOU FEEL COMFORTABLE SHARING IT.

What did you expect to happen?

I've had this problem since the update. I open the terminal in one of my client folders and as soon as I want to write something, I get this error.

Client information

  • CLI Version: 0.38.0
  • Git Commit: 3f0873a83
  • Session ID: 2151c29d-79b1-4c10-9b0a-0b0193fab170
  • Operating System: darwin v22.22.1
  • Sandbox Environment: no sandbox
  • Model Version: gemini-3-flash-preview
  • Auth Type: oauth-personal
  • Memory Usage: 271.5 MB
  • Terminal Name: Warp(v0.2026.04.08.08.36.stable_05)
  • Terminal Background: #121212
  • Kitty Keyboard Protocol: Supported

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No response

Anything else we need to know?

No response

extent analysis

TL;DR

The error is likely due to exceeding the maximum allowed function declarations in the GenerateContentRequest proto, and reducing the number of function declarations may resolve the issue.

Guidance

  • Review the code to identify where the function declarations are being made and reduce the number to 512 or less.
  • Check the API documentation to see if there are any alternative methods for generating content that do not have this limitation.
  • Verify that the error is not being caused by a recursive function call or other infinite loop that is generating a large number of function declarations.
  • Consider reaching out to the API support team for further assistance if the issue persists.

Example

No code snippet is provided as the issue does not include specific code details.

Notes

The solution may vary depending on the specific use case and implementation details, which are not provided in the issue.

Recommendation

Apply workaround: Reduce the number of function declarations to 512 or less, as this is the most likely cause of the error and is a straightforward solution to implement.

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