chatgpt-dev-mode

Scaffold and launch ChatGPT Developer Mode MCP servers in minutes. Runs via npx, generates OAuth or non-OAuth servers, required search/fetch tools, and JSON-RPC handlers. Built-ins: PKCE OAuth, Supabase auth, Fly.io deploy, dev scripts, tests, sample tools (search, fetch, analyze, generate). Production-ready defaults, clear docs. TypeScript-first.!

ChatGPT MCP Developer Mode - Complete Tutorial

Table of Contents

1. Introduction
2. What's New in Developer Mode
3. Requirements & Limitations
4. Option 1: Non-OAuth Implementation
5. Option 2: OAuth Implementation with Supabase
6. Deployment to Fly.io
7. Common Gotchas & Solutions
8. Testing Your MCP Server
9. Troubleshooting

Introduction

ChatGPT's Developer Mode with MCP Server Tools support was officially announced on September 9th, 2025, marking a significant milestone in AI-developer integration. This feature enables ChatGPT to interact with custom MCP (Model Context Protocol) servers, providing unprecedented extensibility and real-world integration capabilities.

What is MCP?

Model Context Protocol (MCP) is an open protocol that standardizes how AI assistants connect with external data sources and tools. It uses JSON-RPC 2.0 for communication and supports:

• Custom tools/functions
• Resource access
• Authentication (OAuth 2.0)
• Real-time capabilities
• Persistent connections

What's New in Developer Mode

September 2025 Launch Features

The September 9th, 2025 announcement introduced groundbreaking capabilities:

Core Features

• MCP Server Integration: Direct connection to custom MCP servers
• Tool Execution: ChatGPT can now execute custom tools on your servers
• OAuth 2.0 Support: Production-ready authentication and authorization
• Dynamic Tool Discovery: Automatic discovery and registration of available tools
• Persistent Sessions: Maintain state and context across conversations
• Real-time Interaction: Bi-directional communication with external services

Significant New Capabilities

1. Custom Tool Creation: Define any function or API as a tool

   • Database queries
   • File system operations
   • API integrations
   • Custom business logic

2. Authentication & Security:

   • OAuth 2.0 Authorization Code Flow with PKCE
   • Dynamic client registration
   • Secure token management
   • User-specific data access

3. Resource Management:

   • Access to files, databases, and APIs
   • Resource permission control
   • Rate limiting and quotas

4. State Persistence:

   • Session management across conversations
   • User context preservation
   • Transaction support

5. Enterprise Integration:

   • Connect to internal tools and databases
   • Custom authentication providers
   • Compliance and audit logging

How to Enable Developer Mode

Accessing Developer Mode in ChatGPT

Since the September 9th, 2025 launch, Developer Mode is available to all ChatGPT users:

1. Open ChatGPT Settings:

   • Navigate to https://chatgpt.com
   • Click on your profile icon
   • Select "Settings"

2. Navigate to Connectors:

   • Go to "Connectors" in the settings menu
   • Select "Advanced Settings"
   • Enable "Developer Mode (beta)"

3. Create a New Connector:

   • Click "Create" next to "Browser connectors"
   • You'll see the "New Connector" modal

Configuring Your MCP Server

In the New Connector modal, fill in the following:

1. Basic Information:

   • Icon (optional): Upload a 128x128px icon
   • Name: Enter a name (e.g., "Custom MCP Tool")
   • Description (optional): Brief explanation of what it does

2. Server Configuration:

   • MCP Server URL: https://mcp-oauth-server.fly.dev (or

... View full README on GitHub