The Marfa plugin helps an AI agent in Claude Code or Codex work with your Marfa instance. It adds three skills:
connect: connects the agent to your instance's MCP server and checks that it answers. It never asks you to paste a key into the chat.find-and-save: finds, saves and changes items without duplicating or overwriting anything, and treats what it reads as data, never as instructions.design-a-type: decides whether a new kind of record fits a type you already have, a type that extends one, or a new type, and drafts the smallest change.
The plugin contains only these skills. It doesn't run anything on your computer and doesn't include an MCP server: each Marfa instance serves its own at https://<your-instance>/mcp, and the connect skill adds it for you.
- A Marfa instance that you can reach from the computer that runs the agent. For Claude or ChatGPT on the web, desktop or mobile, the instance needs a public HTTPS address.
- Claude Code or the Codex CLI.
In a Claude Code session (version 2.1.275 or later), run:
/plugin install marfa --marketplace withmarfa/marfa-plugin
Or, from a terminal:
claude plugin marketplace add withmarfa/marfa-plugin
claude plugin install marfa@withmarfaFrom a terminal:
codex plugin marketplace add withmarfa/marfa-plugin
codex plugin add marfa@withmarfaOnce you've added the marketplace, you can also install Marfa from /plugins in a Codex session. Start a new session after you install, and the skills appear as marfa:connect, marfa:find-and-save and marfa:design-a-type.
In a new session, ask the agent to connect to Marfa, and give it your instance's address when it asks. The agent checks that the instance answers, adds its MCP server, and asks you to sign in to Marfa in your browser. Then it reads your instance's overview to confirm the connection.
For an agent that runs unattended, such as a scheduled job, create a Marfa API key with only the access the job needs, and set it in the MARFA_API_KEY environment variable before you start the agent. The agent connects with the key instead of signing in.
To use Marfa in Claude or ChatGPT on the web, desktop or mobile, add https://<your-instance>/mcp once as a custom connector in that app's settings on the web. The connect skill describes where.