# MCPJam Inspector

> Local development client for ChatGPT Apps SDK with full widget emulator, OAuth debugger, and LLM playground for testing MCP servers.

MCPJam Inspector is a local development client designed for building and testing ChatGPT Apps SDK applications. It provides a complete widget emulator that simulates ChatGPT's behavior, eliminating the need for ngrok or a ChatGPT subscription during development. The tool functions like Chrome DevTools for ChatGPT Apps, exposing all `windows.openai` API calls and JSON-RPC traffic.

- **ChatGPT Apps Builder** - Functions as a full emulator that exposes all API calls and JSON-RPC traffic, providing complete simulation of ChatGPT's behavior for local development and testing.

- **OAuth Debugger** - Visualizes and debugs MCP authorization flows, allowing developers to verify that OAuth implementations conform to the MCP specification at every step of the process.

- **LLM Playground** - Offers 1:1 emulation with ChatGPT, enabling testing of ChatGPT Apps against different models including frontier models like GPT-5 for free, with multiple display modes available.

- **Server Primitives Testing** - Supports testing of server primitives including tools, resources, and prompts for comprehensive MCP server validation.

- **Collaboration Features** - Includes team collaboration capabilities such as sharing tools and supporting up to 3 users per team on the free plan.

- **Cross-Platform Availability** - Available as both a CLI tool via npx and as downloadable desktop applications for macOS and Windows.

To get started, run `npx @mcpjam/inspector@latest` in your terminal or download the desktop app for your platform. The tool provides immediate access to test MCP servers locally without complex setup requirements.

## Features
- ChatGPT Apps widget emulator
- OAuth debugger for MCP authorization flows
- LLM playground with frontier models
- Server primitives testing (tools, resources, prompts)
- JSON-RPC traffic inspection
- windows.openai API call exposure
- Dynamic client registration for OAuth
- Collaboration features with tool sharing
- Multiple display modes
- CI/CD integration for tests
- Security and evals agent
- Server quality analysis agent

## Integrations
ChatGPT Apps SDK, GPT-5, OpenAI API

## Platforms
WINDOWS, MACOS, WEB, API

## Pricing
Freemium — Free tier available with paid upgrades

## Links
- Website: https://www.mcpjam.com
- Repository: https://github.com/MCPJam/inspector
- EveryDev.ai: https://www.everydev.ai/tools/mcpjam-inspector