Stitch MCP not working with API key

Stitch
1

Tried to setup MCP server on antigravity and gemini cli both failed:
antigravity : error bad request. connection closed
gemini cli :
MCP tool ‘list_projects’ reported tool error for function call: {“name”:“list_projects”,“args”:{}} │
│ with response: [{“functionResponse”:{“name”:“list_projects”,“response”:{“error”:{“message”:"Streamable │
│ HTTP error: Error POSTing to endpoint: │
│ {“id”:2,“jsonrpc”:“2.0”,“result”:{“content”:[{“text”:"API keys are not supported by this │
│ API. Expected OAuth2 access token or other authentication credentials that assert a principal. See │
│ https://cloud.google.com/docs/authentication\“,\“type\”:\“text\”}],\“isError\”:true}}”,“isError”:true} │
│ }}}]

2

I’m facing the same problem. I’m using Cursor.

1 Like
3

Facing the same problem, can’t use with antigravity.

4

I have just encountered this issue

5

Same issue, solution is using proxy with AUTH.

Please read: Stitch via MCP | Stitch

Fix for Antigravity + Stitch MCP (Windows)

If you follow the official Stitch MCP docs and Antigravity fails with errors like:

  • Bad Request

  • client is closing

  • invalid character 'd' looking for beginning of value

This is the correct working setup:

1) Install Google Cloud CLI

Install from Google Cloud SDK installer.

Then login:

gcloud auth application-default login
gcloud config set project YOUR_PROJECT_ID
gcloud auth application-default set-quota-project YOUR_PROJECT_ID

Enable Stitch API:

gcloud services enable stitch.googleapis.com --project=YOUR_PROJECT_ID

2) Configure Antigravity MCP (STDIO proxy)

Do NOT use serverUrl: https://stitch.googleapis.com/mcp (API key / bearer token method is unstable).

Use local proxy instead:

"stitch": {
  "command": "npx.cmd",
  "args": ["-y", "@_davideast/stitch-mcp@latest", "proxy"],
  "env": {
    "STITCH_USE_SYSTEM_GCLOUD": "1",
    "GOOGLE_CLOUD_PROJECT": "YOUR_PROJECT_ID",
    "CI": "1",
    "DOTENV_CONFIG_QUIET": "true",
    "DOTENV_QUIET": "true",
    "NO_COLOR": "1"
  }
}

Restart Antigravity.

3) If you get invalid character 'd'

That means dotenv is printing logs like:

[dotenv@...] injecting env...

Fix: remove/rename .env file or keep DOTENV_QUIET=true in env.

1 Like
6

Great !!! It works !!!