A full-stack debugging and evaluation platform for MCP server developers, integrating app building, multi-model comparison chat, OAuth compliance validation, and CI/CD automated testing capabilities.
Core Positioning#
MCPJam Inspector is maintained by MCPJam Inc, addressing high debugging barriers in MCP server development (typically requiring ngrok or ChatGPT/Claude subscriptions), complex OAuth compliance validation, lack of free tools for multi-model tool call comparison, and absence of end-to-end regression testing.
Capabilities & Features#
Development & Debugging#
- App Builder: Interact with LLMs or manually invoke tools within the panel, compatible with OpenAI Apps SDK and MCP app UIs.
- App UI Simulator: Chrome DevTools-style, supporting desktop/tablet/mobile view switching, locale switching, CSP simulation, dark/light mode, hover & touch interaction, safe area insets simulation.
- MCP Server Debugging: Manually run tools/resources/resource templates/prompts/elicitation flows with full JSON-RPC observability logs.
Chat & Model Evaluation#
- Multi-model Chat: Multi-server multi-model conversations with built-in free frontier model access. Chat/Trace/Raw views, up to 3 models side-by-side, token usage visibility.
- Evals: Define test cases with expected tool calls, run across multiple LLMs and track accuracy metrics for regression detection.
Security & Compliance#
- OAuth Debugger: Guided MCP OAuth compliance checking, covering OAuth spec versions 03-26, 06-18, 11-25, supporting DCR, client pre-registration, CIMD.
Collaboration & Extension#
- Workspaces: Server group sharing and real-time team sync.
- Skills: Use local reusable behaviors to extend models in Chat and App Builder, data stays on-device.
Engineering Integration#
- Run conformance, E2E tests, and evals through GitHub Actions/GitLab CI pipelines as PR gates.
Architecture#
- npm workspaces Monorepo with 6 sub-packages:
sdk(@mcpjam/sdk),cli(@mcpjam/cli),mcpjam-inspector(@mcpjam/inspector),design-system,soundcheck(eval/testing),mcp. - Core package split into
client/andserver/directories. - Runtime independence from
@modelcontextprotocol/sdkenforced viacheck:mcp-v1-runtime-importsscript. - Frontend: TypeScript (98.6%), React-based, with
react-force-graph-2dand isolateddesign-systempackage. - Version management via
@changesets/cli. - Docker defaults to
127.0.0.1:6274; Web app enforces HTTPS-only MCP server URLs.
Installation#
Hosted Web App: https://app.mcpjam.com (HTTPS-only)
Terminal: npx @mcpjam/inspector@latest (Node.js 20+)
Docker: docker run -p 127.0.0.1:6274:6274 mcpjam/mcp-inspector
Desktop: Mac/Windows installers supporting HTTP/S and STDIO (download links TBD).
CLI & SDK#
- CLI (@mcpjam/cli): probe, OAuth doctor, tool/resource checks, evals.
- SDK (@mcpjam/sdk): Programmatic access to inspection and evaluation primitives.
- Both integrable into CI/CD pipelines for automated gates.
Ecosystem Partners#
Stytch (OAuth provider), xMCP (TypeScript MCP framework), Alpic (MCP server hosting). Built-in railway.json for one-click Railway deployment.
Unconfirmed Information#
- Exact version number (changesets-managed, not in README)
- Docker Hub image availability
- Desktop app download links
- Evals sub-module independent license details
- Discord community invite link