ChatGPT web and local Codex clients use different MCP setup paths. OpenAI’s current MCP documentation states that ChatGPT web uses remote MCP-backed tools supplied by installed plugins, while the ChatGPT desktop app’s Codex surface, Codex CLI, and the IDE extension can connect directly and share local MCP configuration.
ChatGPT web
ChatGPT web does not read your local Codex config.toml. A SeatLayer tool must
be available through an installed workspace-approved plugin before Chat or Work
can use it.
SeatLayer Designer MCP is currently a chart-scoped Preview, not a promise that a public SeatLayer plugin is available in every ChatGPT workspace. If your workspace does not show an approved SeatLayer plugin, use a supported direct remote-MCP client such as Codex or Claude instead.
ChatGPT desktop app with Codex
Use the Codex MCP setup:
- Open Settings → MCP servers.
- Add a Streamable HTTP server using the URL from SeatLayer’s Dashboard → Agent connections.
- Restart, authenticate, and confirm the server with
/mcp.
Follow connect Codex for the complete check and Designer MCP for chart-authoring rules.