What Context7's MCP actually does
Context7 puts current library docs into the prompt. Two tools, one URL, and why the listing sends you there.
Context7 is a documentation server from Upstash. An agent that only knows its training data will invent APIs. Context7 fetches the current docs for a library and puts them in the prompt before the agent writes the code.
The two tools
The README names two MCP tools. resolve-library-id turns a plain name, plus the question you are asking, into a Context7 library id such as /supabase/supabase. query-docs takes that id and the question and returns the matching documentation. There is also a ctx7 command line, which is a different mode and does not require the MCP server.
The remote endpoint in the README is https://mcp.context7.com/mcp. An API key is recommended. You get one from Context7, and you send it as a bearer token. PlugMCP does not hold that key for you unless you separately host a copy.
When it is the right server
- You are generating code against a library that moves: Next.js, Supabase, the SDK you upgraded last week.
- You already know the library id and want to skip the search. Put the id in the prompt.
- You want a specific version. Say the version. Context7 matches docs to it.
It is the wrong server if you need to click around a live website, run a browser, or change a production database. Those are other MCPs. Context7 reads documentation.
On the PlugMCP page
The listing upstash-context7 is the GitHub project. The install block copies the publisher URL. The README tab is the README we crawled. The tools tab lists resolve-library-id and query-docs. Add to Cursor uses that URL, not a PlugMCP proxy.