01
Open MCP servers in Settings
Click ⚙️ in the lower-left of Codex App, then click Settings. In the left sidebar, click MCP servers.
>_ one setup
Install Codex pets — no terminal needed.
One setup in your Codex App. Then install pets by typing /pet in any thread.
Four steps, in your Codex App.
02
Add hatchery.pet
Above the list, click + Add server. Change the server type from STDIO to Streamable HTTP, then fill in:
- Name: hatchery
- URL: https://mcp.hatchery.pet/mcp
Leave everything below the URL blank — you only need Name, type, and URL. Click Save.
03
Sign in once
Back at the MCP servers list, find the hatchery row and click Authenticate. A browser tab opens. Sign in with Google, then click Authorize. The browser shows “Authentication complete.” You can close the tab.
Move quickly — Codex listens for the callback for a limited time, so click Authorize as soon as the consent screen appears.
04
Wake up your pet
In any Codex thread, type /pet in the composer. Pick a pet from the catalog Codex shows you. The pet appears in the top-right and follows you across windows.
What this does.
Codex can now browse the hatchery.pet catalog, search by vibe, and install pets on your behalf. Every install lands in your library with a Codex source badge.
Troubleshooting.
The Authenticate button is still there after I signed in.
Quit Codex App fully (Cmd+Q) and reopen it. The settings UI can get stuck — the underlying connection is fine, the row just needs a refresh.
My browser said the site couldn’t be reached after I signed in.
Codex closes the listener if too much time passes between clicking Authenticate and clicking Authorize. Remove the hatchery row, re-add it, and click Authorize within a few seconds.
I clicked Authenticate but no browser tab opened.
Check your browser’s pop-up blocker. If it’s blocked, allow pop-ups from Codex App and try again.
The /pet command does nothing in Codex.
Type /mcp in a thread to check whether hatchery shows as Authenticated. If it shows Not authenticated, restart Codex App fully.
I want to switch to a different pet.
Settings → Appearance → Pets → Select a different one. Or install another pet from the catalog and pick it there.
What’s next.
Browse the catalog
Scan the launch roster of pets by sprite, state, rarity, and creator.
Or install from your terminal
Power-user path: one command per pet, no GUI.
Read the API reference
The public REST API for the catalog, manifests, and install telemetry. Use it from your own clients or to inspect what the MCP server returns.