authorizationResponseIssParameterSupported · iss

Gemini CLI rejects OAuth callbacks that lack the iss parameter · id PC-055 · checked_on 2026-10-31 · license CC-BY-4.0

Error strings

Situation

Login to an MCP server fails at the callback step in Gemini CLI.

Symptom

The callback is rejected although the code is valid.

Cause

Gemini CLI requires the iss parameter in the authorization callback when the server metadata declares support, and also when it cannot discover metadata.

Fix

Return iss from the authorization server, or set authorizationResponseIssParameterSupported to false in the oauth block for that server.

Snippet

"oauth": { "authorizationResponseIssParameterSupported": false }

Verify

Repeat the login and confirm the callback is accepted.

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.

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