Troubleshooting MCP connections (Claude, Cursor, Codex, and more)

Supermemory's MCP server lives at https://mcp.supermemory.ai/mcp and supports OAuth sign-in and API-key auth. Most connection problems fall into a few buckets:

1. Authentication errors (401 / 403)

• Sign out and back in inside the client — stale OAuth tokens are the most common cause of sudden 401s.
• Make sure you complete the OAuth flow with the same account that owns your data. Signing in with a different Google/GitHub identity creates a second, empty account — if your memories "disappeared", check which account you're connected as.
• A 403 on specific operations usually means the key or OAuth grant is read-only or scoped to a different organization.

2. Repeated login prompts or disconnects

• Update the client and the Supermemory plugin/extension to the latest version, then restart the client fully.
• If a browser tab keeps opening asking you to log in, complete the flow once in your default browser while signed in to the right account, then restart the editor.

3. Client-specific quirks

• Some CLIs are strict about the OAuth spec; if the automated flow fails, configure the server with an API key instead: set the server URL to https://mcp.supermemory.ai/mcp with header Authorization: Bearer sm_<your key>.
• If the API key works on the REST API but not on MCP, tell support exactly that — it pinpoints the issue quickly.

Still stuck?

Write in with: the client name and version (e.g. Cursor 1.4, Claude Desktop), your OS, whether you used OAuth or an API key, and the exact error text. Screenshots of the error help a lot.