What are ChatGPT Apps?
OpenAI announced the support for Apps within ChatGPT. ChatGPT Apps unlock interactive experiences that live inside ChatGPT conversations, allowing applications to respond to natural language with in-chat interfaces (like maps or playlists).Guide for deploying your application
TL;DR
- Create an
MCPApp()in your python server code - Install the
mcp-agentlibrary - Deploy with the
mcp-agentCLI
1) Prerequisites
- Python 3.10+
2) Install dependencies
Usinguv (recommended):
3) Minimal code change: create an MCPApp()
MCPApp is the constructor for defining an MCP Application. The mcp-agent library looks for the MCPApp when configuring the application in the hosted cloud platform.
Make sure your server creates an MCPApp() and wires it to your FastMCP instance.
main.py
4) Add deployment config & secrets
Create two files at the repo root:mcp_agent.config.yaml
mcp_agent.secrets.yaml
5) Deploy to mcp-agent cloud
Withuv:
venv:
Support for OAuth coming soon!
6) Test in ChatGPT
- Enable Developer Mode in ChatGPT.
- Go to Settings → Connectors and add your app’s MCP server.
- Use your cloud URL, making sure it ends with
/sse.
ChatGPT connects to the SSE endpoint, so the
/sse suffix is required.Troubleshooting
- 404 / Connection errors in ChatGPT: Ensure your URL ends with
/sseand your code’smessage_pathis/sse/messages. - Auth errors: If you are unable to deploy because of an Auth issue, make sure you run
mcp-agent login. If you are unable to access your ChatGPT app, make sure you deployed with the--no-authconfiguration to make sure you can access your application. - MCP Inspector: If you want to test without ChatGPT, you can use MCP Inspector (a debugging tool) for MCP servers to validate to make sure your MCP application is properly configured.
