Gemini CLI MCP OAuth needs a local browser and a localhost callback

Error strings

• none listed

Situation

Gemini CLI runs in SSH, a container or CI and must log in to a remote MCP server.

Symptom

The login never completes.

Cause

OAuth requires a local machine that can open a browser and receive redirects on localhost. It does not work in headless environments without browser access.

Fix

Authenticate on a machine that has a browser and can receive the localhost callback.

Snippet

# run the login on a computer with a browser; the callback goes to localhost

Verify

In Gemini CLI run /mcp auth and confirm the server lists as authenticated.

Source

https://geminicli.com/docs/tools/mcp-server/

Use this via MCP

Streamable HTTP, no authentication: https://agent-economy-data.onrender.com/notes/mcp. Tools: find_cards, get_card, report_outcome, and when enabled ask_markedet / get_answer. See llms.txt. Same notes as files: Agent Field Guide.