MongoDB Initialization Fails: "Error: calling initialize: EOF" in Google Antigravity

[Tsaihemanth150]

Title: Error: calling "initialize": EOF when configuring GitHub MCP in Google Antigravity

Summary:
While configuring the GitHub MCP server inside Google Antigravity, the initialize call fails with:
Error: calling "initialize": EOF
Using local URI: mongodb://localhost:27017/

Steps to reproduce:

1. Open Antigravity and configure GitHub MCP to use local MongoDB at mongodb://localhost:27017/
2. Start the MCP / run the initialization step

Observed:
Initialization fails with Error: calling "initialize": EOF and connection fails.

Suspected cause:
Antigravity appears to run agent processes in an isolated environment that cannot reach the host's localhost:27017. Using 127.0.0.1 or exposing the host port or using an external DB may be required.

Diagnostic data to attach:

• Output of mongosh "mongodb://127.0.0.1:27017/" from host.
• ss -lnpt | grep 27017 (or netstat) output.
• If possible, output of nc -vz 127.0.0.1 27017 from Antigravity agent terminal.
• Antigravity version & OS, plus MCP plugin/version.

Workarounds tried:

• Using 127.0.0.1 (replace if tested)
• Starting mongod on host

Request:
Please advise Antigravity-specific configuration to allow MCP/agent processes to reach host services, or confirm required networking config for local DBs.

Links:

• Antigravity docs: https://antigravity.google/

[github-actions]

Thanks for opening this issue. The ticket MCP-302 was created for internal tracking.