MCP assistants
ChatGPT and Codex
ChatGPT reaches Lymi through a custom MCP plugin, and the Codex CLI through its MCP config. Both sign in with OAuth; neither takes an API key.
https://my.lymi.app/mcpOnce connected, ask it to add the cards from a lesson, list what is due, or find a card. What it can and cannot do is on Connect an assistant.
ChatGPT
Open Plugins on the web, choose the plus button, then Add custom MCP server. Name it Lymi and paste the server URL above. Choose OAuth authentication and Client ID Metadata Documents (CIMD) when asked how the client identifies itself. Lymi does not use dynamic client registration.
Review the connection warning and choose Create as a plugin. Complete Lymi’s sign-in and approve the access you want to grant. Install the resulting plugin, then select it with @ in a new chat.
Account and workspace permissions can affect whether this option is available. If your interface still uses Apps, follow OpenAI’s current connection guide for your account.
Codex CLI
Add the server, then sign in. Codex handles the OAuth round trip for you.
codex mcp add lymi --url https://my.lymi.app/mcp
codex mcp login lymiThat writes an entry into ~/.codex/config.toml. You can also write it yourself:
[mcp_servers.lymi]
url = "https://my.lymi.app/mcp"Leave bearer_token_env_var out. That field is for servers that take a static token, and Lymi does not: it wants the OAuth flow, so that every grant is one you approved and can revoke.
When it does not connect
- Sign-in is refused. An account made with an email address and a password cannot sign in until the address is confirmed. Open the link in the confirmation email, then connect again.
- Registration fails. Lymi has no dynamic client registration, by design. ChatGPT and current Codex use a Client ID Metadata Document instead. If an older Codex tries to register, update it, or run
codex mcp login lymi --oauth-client-registration cimd. - Writes are refused. The connection was granted read only. Reconnect and leave write ticked on the consent screen.