chatgpt-app-basic

{{.ServerName}} MCP Server

A simple Model Context Protocol (MCP) server written in Go that provides a greeting tool with a ChatGPT App UI.

Features

• MCP Tool: A greet tool that says hi to any person
• ChatGPT App UI: Interactive web interface with a dropdown and text input
• Structured Data: Returns both text content and structured data for the UI

Building

Build the Docker image:

docker build -t {{.ServerName}}:latest .

Running with Docker Compose

Start the gateway with the {{.ServerName}} server in streaming mode:

docker compose up

The gateway will start in streaming mode on port 8811 and connect to the {{.ServerName}} server. You can then interact with it through MCP clients using HTTP streaming at http://localhost:8811.

ChatGPT App UI Setup

To use the ChatGPT App UI with this server:

1. Expose the gateway publicly with ngrok:

   ngrok http 8811
   

2. Open ChatGPT Settings on ChatGPT.com (not the app), then click "Apps and Connectors"

3. Enable Developer Mode at the bottom of the settings pane

4. Create a new connector:

   • Click the "Create" button at the top right
   • Give the connector a name (e.g., "{{.ServerName}}")
   • Add your ngrok URL
   • Set "Authentication" to None

5. Use the connector in ChatGPT:

   • Ask ChatGPT: "call the greet tool from the {{.ServerName}} server"
   • The interactive UI will appear inline
   • Select a greeting type (Hi, Hey, or Hello) from the dropdown
   • Enter a name in the text field
   • Click "Greet Me" to make the tool call

The UI will call the MCP tool via window.openai.callTool() and display the greeting response with smooth animations.

Tools

• greet: Says hi to a specified person
  • Input: name (string) - the person to greet
  • Input: greetingType (string, optional) - type of greeting (Hi, Hey, or Hello)
  • Output: A greeting message
  • UI: Interactive widget with dropdown, form, and response display

Development

To modify the server:

• Edit main.go to change the tool logic
• Edit ui.html to customize the UI
• Rebuild the Docker image with docker build -t {{.ServerName}}:latest .
• Restart the gateway with docker compose up