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1. Open MCPJam

Web: HTTPS only, runs in the browser with no install. Server links can be shared with teammates. Terminal and Desktop: HTTP/S and local STDIO.

Web App

HTTPS only. No install. Share with your team.

Terminal

npx @mcpjam/inspector@latest. HTTP/S and local STDIO.

Desktop App

Mac or Windows. HTTP/S and local STDIO.

2. Draw something

On first launch, MCPJam connects the Excalidraw sample server (diagramming MCP app) and opens the Playground with this prompt:
Draw me an MCP architecture diagram
Press Send. The diagram renders in the app. No API key, ngrok, or ChatGPT/Claude subscription needed. Sequence: tool call → widget → inspect.
Use the widget debug icons to open tool input/output, CSP activity, widget state, and JSON-RPC for that result.

3. Connect your own server

Open Servers in the left sidebar. Click Add server.
  • HTTP: Paste a URL ending in /mcp. The web app accepts HTTPS URLs only. Desktop and Terminal accept HTTP or HTTPS. Add a bearer token or use the OAuth Debugger if the server requires auth.
  • STDIO (Desktop and Terminal only): Paste a command such as npx -y @modelcontextprotocol/server-everything. Not available in the web app. See Hosted App.
Each Connected server is available in the Playground, Tools, Prompts, and Resources. Connect more from Servers anytime.

4. Where to go next

Playground

IDE-style workspace for developing against your MCP servers. Chat with frontier models, invoke tools by hand, render OpenAI Apps SDK and MCP app widgets, and inspect every step via Chat / Trace / Raw. Compare up to 3 models side by side; debug widgets with the emulator (iframe, window.openai, CSP, device frames, locale).

OAuth Debugger

Step through your MCP authorization flow and inspect each stage. Check conformance across protocol versions (03-26, 06-18, 11-25) and client registration paths: Dynamic Client Registration (DCR), client pre-registration, and CIMD.

Projects

Group servers; share configuration with your team