MCPJam Inspector
A local tool to test and debug MCP servers: chat with tools, inspect calls and run evals across clients
Medium risk
We rate an entry medium when the tool runs code, makes network calls or reads project files. Check what exactly it does before installing.
Why this level
- Runs a local service and connects to your MCP servers
- Invokes the tools of the server under test
Install
Manual install
npx @mcpjam/inspector@latestStarts the inspector interface locally.
This is third-party code. Review the repository files before installing.
What it does
The tool runs locally and connects to your MCP server so you can see it the way different clients do. You can call tools by hand, read responses and traces, and check OAuth authorization. A separate evals mode runs scenarios across several client configurations and shows where the server behaves differently. That helps catch mismatches before the server reaches ChatGPT, Claude or Cursor. It ships as an npx command and a Docker image.
Who it is for. For MCP server developers and QA engineers who need to test a server before release.
Good fit when
- You need to call server tools by hand and inspect responses
- You need to check how the server looks to different clients
- You need to debug OAuth authorization of an MCP server
Not a fit when
- You do not build an MCP server and only use a ready one
- You need continuous production monitoring rather than a one-off check
Example request
Start MCPJam Inspector and test my local MCP server: call every tool and show the errorsLimitations
It is a development tool, not a finished agent. The interface runs locally, but cross-client behavior evals need model provider keys, whose availability from Russia should be checked separately.
How to disable. No separate install is needed with npx. The Docker image is removed with standard Docker commands.
Security check
- Runs a local service and connects to your MCP servers
- Invokes the tools of the server under test
README in short
The README presents MCPJam as a platform to test and debug MCP servers, MCP apps and ChatGPT apps. It shows npx and Docker startup and describes calling tools by hand, viewing traces and checking OAuth. It also covers cross-client evals that run server behavior across many client configurations. The project is open source and actively developed.
FAQ
Do I need an account?
Not for the local inspector. Cross-client evals require model keys from the respective providers.
How do I run it in Docker?
There is an mcpjam/mcp-inspector image that serves the interface on a local port.
Related
A skills library that gives coding agents a development process: brainstorming, planning, TDD, subagents and code review
Skills for real engineers by Matt Pocock
Skills For Real Engineers
Small composable skills for engineering with agents: plan grilling, TDD, bug diagnosis, code review and architecture
GitHub toolkit for spec-driven development: the specify CLI adds agent commands and skills to a project, from principles to implementation
Reference MCP servers
Model Context Protocol servers
Official reference MCP servers: Filesystem, Fetch, Git, Memory, Sequential Thinking, Time and Everything