MCP connections fail in a small number of predictable ways. Work through them in order before changing anything else.
- Check the endpoint. It is exactly
https://mcp.argorant.com/mcp. A missing/mcppath is a frequent cause. - Complete the sign-in window. The connection uses OAuth, so a window opens and you sign in with your Argorant account. If it was blocked or closed early, the connector stays unauthorized. Allow popups and retry.
- Check the client supports custom connectors. In ChatGPT they are available on Pro, Business and Enterprise via developer mode. Elsewhere, use the API key path instead.
- Remove and re-add the connector rather than editing it, if a half-finished authorization left it in a bad state.
For Claude Code the command is claude mcp add --transport http argorant https://mcp.argorant.com/mcp. In Cursor it is Settings then MCP then Add Server with the same endpoint. Native app schemes such as cursor:// are supported during the OAuth redirect, so a desktop client returning to itself is normal.
If MCP is not available in your client at all, nothing is lost. Use an API key with the REST API, which every client can reach. The setup prompt tries MCP first and falls back to a key automatically.
Once connected, ask for a count. It is free, so it is a safe test.