Mermail MCP

Configure, verify, and troubleshoot the hosted Mermail MCP server in Codex, Claude Code, Cursor, or another MCP client. Use when installing Mermail, setting MERMAIL_API_KEY, mapping x-api-key authentication, checking connection status, diagnosing 401 or revoked-key errors, or confirming tool discovery.

Connect Mermail MCP

Configure the hosted Streamable HTTP server without storing credentials in project files. Read platforms.md for the exact client format.

Setup

1. Create an API key in Mermail workspace settings and copy it once.
2. Store it as MERMAIL_API_KEY in the platform's secret environment. Never ask the user to paste it into chat.
3. Configure https://console.mermail.app/mcp and map the environment variable to the x-api-key header using the platform-specific syntax.
4. Restart or reload the client so its desktop process receives the environment variable.
5. Run node scripts/check-connection.mjs from this skill directory, or inspect the server with the client's MCP status command.
6. Confirm that initialization succeeds and exactly 63 tools are discoverable.

Troubleshoot

• Missing environment variable: set MERMAIL_API_KEY in the environment that launches the client, then restart it.
• 401: check that the header is named x-api-key, the key starts with sk-proj-, and the key is not revoked.
• 403: use a key bound to the requested workspace and verify permissions.
• 402: verify Developer-plan access and remaining credits.
• 429: wait for the RPM window; do not rotate keys to bypass limits.
• Tool mismatch: refresh the plugin and compare against the production server card.

Do not print the key, write it into tracked JSON, or use command-line arguments that may persist in shell history.