ChatGPT on the web and Codex in the ChatGPT desktop app connect to MCP servers in different ways. Once connected, either can build and review seating charts and set up events in SeatLayer. Neither can hold, book, or sell seats; see what the Designer MCP covers. OpenAI documents its current setup in its MCP documentation.
The server URL is on Dashboard → Agent connections in SeatLayer. In
production it is https://mcp.seatlayer.io/mcp. For ChatGPT on the web, use
https://mcp.seatlayer.io/mcp?tools=build: it lists the 63 tools for
building, editing, pricing, checking and publishing, so each turn carries less
than half the tool definitions. Add ,trace to trace a floor-plan image. For
Codex, use the plain URL. See toolsets.
ChatGPT on the web
ChatGPT web does not read a local Codex config.toml. It uses custom apps that
a workspace admin allows.
- A ChatGPT workspace admin turns on developer mode or custom MCP apps in the workspace settings.
- Create a custom app and paste the SeatLayer server URL.
- Connect the app. ChatGPT opens SeatLayer in your browser.
- Sign in to SeatLayer and approve the grant (see the consent screen below).
- Turn the app on in a conversation, and review each confirmation before a write or publish action.
Write-capable MCP apps on ChatGPT web depend on your ChatGPT plan and on OpenAI’s rollout. That limit comes from ChatGPT, not SeatLayer. If your workspace cannot add the app, use Codex or Claude instead.
ChatGPT desktop app with Codex
The desktop app’s Codex surface shares MCP configuration with the Codex CLI and IDE extension:
- Open Settings → MCP servers.
- Add a Streamable HTTP server named
SeatLayerwith the server URL. - Restart, choose Authenticate, and approve the grant in the browser.
- Run
/mcpto confirm the server is connected.
Follow connect Codex for the CLI setup and a safe first prompt.
The SeatLayer consent screen
Whichever client you use, SeatLayer shows the same screen, and the person approving needs the SeatLayer admin role:
- Workspace: the workspace the agent works in.
- One chart or Every chart in this workspace. One chart is the default; a workspace grant lets the agent list and create charts there.
- Manage live events: off by default. Turn it on only if the agent should close sections or block seats on events that are already selling.
Never paste a SeatLayer secret key into ChatGPT. The connection uses OAuth tokens that expire hourly and refresh on their own.
Without a connection, ChatGPT can still write a Venue Spec for you to paste into the Designer.
Continue with Designer MCP for the tool list and the chart-building workflow.