MCPJam/inspector

Hosted app  · 
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**MCPJam** is the open-source **testing & evaluations platform for MCP server developers** who ship. Interactively test tools, prompts, resources, and authorization across 16 client configurations and 170+ models. Run evals on test cases, get insights on what's breaking, and gate regressions to secure every deployment.
🚀 Quick start
Open the hosted app. No install needed.
👉 **app.mcpjam.com**
... or run MCPJam locally for HTTP/S and local STDIO servers:
👋🏽 Why MCPJam
Clients like ChatGPT, Claude, and Cursor all read your server differently. MCPJam catches those differences, shows where your server breaks, and tells you how to fix it:
- **Inspect & debug**: Explore your server's tools, resources, and prompts in one place. Test prompts from real LLMs, with full visibility & traces on every JSON-RPC message and OAuth exchange.
- **Cross-client evals**: Score agent behavior across 16 client configurations — ChatGPT, Claude, Cursor, Copilot, and more — to understand how your MCP integrations perform across all users. Track accuracy, latency, and tool-call performance over time.
- **Security & reliability**: Automate conformance & behavior checks in CI/CD to catch regressions before they reach production.
_Trace view: every tool call, agent step, and JSON-RPC message in one timeline._
🔨 Features
| Capability | What it does |
| -------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| **Playground** | Cross-client chat interface that emulates UIs, tool calls, and skills (with full traces). OpenAI Apps SDK and MCP app UIs, text tools, and a Chrome DevTools-style widget emulator. Read more |
| **OAuth Debugger** | Visualize your OAuth & EMA requests step-by-step to find the source of errors. Guided MCP OAuth conformance checks across protocol versions 03-26, 06-18, 11-25, and 2026-07-28; DCR, client pre-registration, and CIMD. Read more |
| **Server Debugging** | Manually run tools, resources, templates, prompts, and elicitation flows with full JSON-RPC logs. |
| **Skills** | Extend models with reusable behaviors in Playground. Local skills are read from your filesystem and never leave your machine; a project can also carry hosted skills, available on accounts where that is enabled. Read more |
| **Workspaces** | Shared server groups with real-time team sync, so everyone tests the same config. Read more |
| **Evals** | Test cases with expected tool calls, run across LLMs, with accuracy metrics over time. Read more |
| **CLI** | Probe servers, run doctor checks, exercise OAuth, and list tools/resources/prompts from your terminal. Read more |
| **SDK** | Programmatically drive inspections, snapshot capabilities, and assert on tool/resource shapes from your own tests. Read more |
| **CI/CD** | Run conformance, E2E tests, evals, and OAuth checks on every PR in GitHub Actions or any pipeline. Read more |
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Playground
Debug your server against a model using tool calls or in-panel chat, with Chat, Trace, and Raw views. Supports the OpenAI Apps SDK and MCP app UIs, text tools, and a Chrome DevTools-style widget emulator so you can iterate on widgets locally.