blocked bug from using MCP server in Antigravity IDE

[Mazen-Embaby]

---

Describe the bug

When using the github-mcp-server with an LLM client or gateway that integrates with the Gemini API (such as Antigravity), tool initialization/registration fails with a 400 INVALID_ARGUMENT error.

This is caused by an invalid JSON Schema definition for the delete parameter within the issue_fields array property of the issue_write tool. The schema defines delete with Enum: []any{true}. Because the Gemini API's protobuf representation only supports string enums (repeated string enum), non-string values like the boolean true are serialized into an empty string (""), which fails the API gateway validation.

Affected version

GitHub MCP Server
Version: v1.5.0
Commit: 8cd03c018525ae0bafc9b3cdb84ec2133e01bac2
Build Date: 2026-06-27T07:57:40Z

Steps to reproduce the behavior

1. Start github-mcp-server in stdio mode.
2. Launch a client that bridges the MCP server's JSON schema tool declarations to the Gemini API (such as Antigravity).
3. Attempt to register the issue_write tool schema with the Gemini API.
4. The Gemini API rejects the request, returning a 400 INVALID_ARGUMENT response indicating enum[0] is empty.

Expected vs actual behavior

• Expected: The issue_write tool schema registers successfully.
• Actual: Registration fails with INVALID_ARGUMENT: enum[0]: cannot be empty because of the boolean enum constraint on the delete parameter. Removing Enum: []any{true} (making it a clean boolean type parameter, which matches the schema used in the granular set_issue_fields tool) resolves the error.

Logs

{
  "error": {
    "code": 400,
    "message": "* GenerateContentRequest.tools[51].function_declarations[0].parameters.properties[issue_fields].items.properties[delete].enum[0]: cannot be empty\n",
    "status": "INVALID_ARGUMENT"
  }
}

Fix

kindly, check the following pull request
fix: remove invalid boolean enum from issue_write delete parameter this appears in antigravity IDE cause error
#2887

[Nithwin]

+1, hitting this exact same issue on Google Antigravity when switching over to Gemini models (works fine on Claude).

Here's the 400 error payload from my session:

{
  "error": {
    "code": 400,
    "message": "* GenerateContentRequest.tools[26].function_declarations[0].parameters.properties[issue_fields].items.properties[delete].enum[0]: cannot be empty\n",
    "status": "INVALID_ARGUMENT"
  }
}