MCP Inspector

license

Apache-2.0(OSI, new code)+MIT(OSI, legacy contributions not yet relicensed)

docs

CC-BY-4.0(documentation other than the specifications

source

public

core features withheld

no

MCP Inspector carries the Model Context Protocol project's transition license - Apache-2.0 for new code, with MIT kept for earlier contributions whose authors have not agreed to relicense - and both are OSI-approved. The whole tool, covering the web, CLI and terminal clients, is in the public repository and runs via `npx @modelcontextprotocol/inspector` with no key or paid tier.

• https://github.com/modelcontextprotocol/inspector recorded 2026-08-13

  Repo page, 10,660 stargazers. Web, CLI and TUI clients plus shared core all in the tree, run from one `npx @modelcontextprotocol/inspector` binary. No paid tier, license key or enterprise directory.

• https://raw.githubusercontent.com/modelcontextprotocol/inspector/main/LICENSE recorded 2026-09-28

  The LICENSE file now carries the MCP transition terms: "All new code and specification contributions to the project are licensed under Apache-2.0" while "Contributions made by authors who originally licensed their work under the MIT License and who have not yet granted explicit permission to relicense remain licensed under the MIT License."

• https://raw.githubusercontent.com/modelcontextprotocol/inspector/main/package.json recorded 2026-09-28

  package.json no longer declares a bare MIT id: beside "author": "The MCP Maintainers and Community", its license field reads "SEE LICENSE IN LICENSE".

• https://raw.githubusercontent.com/modelcontextprotocol/inspector/main/README.md recorded 2026-09-28

  The License section reads "The MCP project is transitioning from the MIT License to Apache-2.0". The tool ships "as a single package, `@modelcontextprotocol/inspector`" and runs with "npx @modelcontextprotocol/inspector". Searched the body for pricing, paid, subscription, license key, premium and hosted: none.

Downloads are measured directly from the npm package, since it is the debugging tool itself rather than an SDK or a dependency of one. That makes the count a direct measurement of the tool's own users, with no adjustment needed to stand for the product.

• https://api.npmjs.org/downloads/point/last-month/@modelcontextprotocol/inspector recorded 2026-09-14

  1,093,328 downloads in the trailing 30 days for @modelcontextprotocol/inspector, window 2026-08-13 to 2026-09-11

MCP Inspector implements the client role only, exercising a server's full primitive set through three surfaces - a web UI, a CLI and a terminal UI - from one binary. What keeps it a step below SDKs such as the MCP Python SDK is the missing server role, not any missing feature, and the README does not state which specification version it targets.

• https://raw.githubusercontent.com/modelcontextprotocol/inspector/main/README.md recorded 2026-09-17

  The README: "A developer tool for inspecting Model Context Protocol (MCP) servers", shipping as one package with three client surfaces - a Vite and React web app, "a scriptable command-line client for automation, CI, and fast agent feedback loops", and an Ink terminal UI - all run through one `mcp-inspector` binary. It inspects servers; it does not implement one.