Connect ChatGPT and OpenAI agents

The server URL is https://app.lobbystack.com/api/mcp. Replace app.lobbystack.com with your own domain if you self-host. ChatGPT connects to it from the internet, so a self-hosted LobbyStack needs a public HTTPS address. See MCP server for the tools each permission unlocks.

ChatGPT

ChatGPT adds custom MCP servers as apps in developer mode, which OpenAI offers on Plus, Pro, Business, Enterprise and Education accounts on the web.

Turn on developer mode

In ChatGPT, open Settings > Security and login and turn on Developer mode.

Create the app

Open ChatGPT’s plugins, click +, and create a developer-mode app. Name it LobbyStack, paste the server URL, and choose OAuth for authentication. Leave any client ID and secret empty; ChatGPT registers itself with LobbyStack.

ChatGPT opens LobbyStack. Sign in, pick the business, uncheck anything ChatGPT shouldn’t do, and click Allow access.

To disconnect, go to Settings > Connected apps in LobbyStack and click Disconnect next to ChatGPT.

OpenAI Responses API

The Responses API calls remote MCP servers for you. Pass an API key in headers:

curl https://api.openai.com/v1/responses \
  -H "Authorization: Bearer $OPENAI_API_KEY" \
  -H "content-type: application/json" \
  -d '{
    "model": "gpt-6-luna",
    "tools": [{
      "type": "mcp",
      "server_label": "lobbystack",
      "server_url": "https://app.lobbystack.com/api/mcp",
      "headers": { "Authorization": "Bearer '"$LOBBYSTACK_API_KEY"'" },
      "require_approval": "always"
    }],
    "input": "Who called yesterday and asked for a callback?"
  }'

require_approval: "always" makes the API stop before each tool call so your code can confirm it. Loosen it only for keys with read scopes.

Codex

Add LobbyStack to ~/.codex/config.toml. Codex reads the API key from the environment variable you name:

~/.codex/config.toml

[mcp_servers.lobbystack]
url = "https://app.lobbystack.com/api/mcp"
bearer_token_env_var = "LOBBYSTACK_API_KEY"

Export LOBBYSTACK_API_KEY in your shell, start Codex, and ask it to call get_business to check the connection.

Get started

General

Agent

Manage

API

AI assistants

API reference

Self-hosting

Connect ChatGPT and OpenAI agents

ChatGPT

OpenAI Responses API

Codex

​ChatGPT

​OpenAI Responses API

​Codex

ChatGPT

OpenAI Responses API

Codex