Context7 MCP Server

About

Context7 is Upstash's documentation-retrieval MCP server, and it exists to solve one specific failure mode: a coding model answering from year-old training data, inventing APIs that were never shipped, or writing config for a package version you are not running. Instead of guessing, the agent calls Context7 and gets version-specific documentation and code examples pulled from the library's own source, injected straight into the prompt. In practice you append "use context7" to a request — "Create a Next.js middleware that checks for a valid JWT in cookies and redirects unauthenticated users to /login. use context7" — and the docs arrive before the code is written. The MCP surface is deliberately two tools. `resolve-library-id` turns a plain library name into a Context7-compatible ID, taking both a `libraryName` and the user's actual `query` so results can be ranked by relevance rather than string match. `query-docs` then fetches documentation for an exact ID such as `/vercel/next.js` or `/mongodb/docs`. You can skip the resolve step entirely by naming the ID in your prompt ("use library /supabase/supabase for API and docs"), and you can pin a version just by mentioning it ("How do I set up Next.js 14 middleware?"). Setup is a single command, `npx ctx7 setup`, which authenticates over OAuth, generates an API key and installs the integration; `--cursor`, `--claude` and `--opencode` target a specific agent, and `npx ctx7 remove` reverses it. Notably it ships in two modes: classic MCP, or a CLI-plus-Skills mode where the agent shells out to `ctx7 library` and `ctx7 docs` commands with no MCP server at all. To wire it manually, point your client at the hosted endpoint `https://mcp.context7.com/mcp` and pass your key as an `Authorization: Bearer` header — a free key from context7.com/dashboard mainly buys higher rate limits. Two honest caveats from Upstash's own README: the indexed library docs are community-contributed, so accuracy is not guaranteed and pages carry a Report button; and the public repo holds only the MCP server, while the API backend, parsing engine and crawling engine are private. Companion packages include the `ctx7` CLI, `@upstash/context7-sdk`, and Vercel AI SDK tool bindings.

Installation

npx ctx7 setup

Setting up Context7

1. 1.Run the setup command

   One command does the whole thing: it authenticates over OAuth, generates an API key and installs the integration. It will ask whether you want CLI plus Skills mode or MCP mode. Target a specific agent with --cursor, --claude or --opencode. Node 18 or newer is required for the CLI itself; the MCP server package needs Node 20.18.1 or newer as of 3.2.5, which dropped Node 18 when it moved to undici 7.

   shell

   npx ctx7 setup

2. 2.Choose CLI plus Skills, or MCP

   CLI plus Skills installs a skill that teaches your agent to run ctx7 library and ctx7 docs as shell commands — no MCP server, no tool schemas loaded into every request, and the docs arrive only when the agent decides to fetch them. MCP mode registers the server so the two tools are always present. On a coding agent that already has a shell, the CLI mode is usually the cheaper choice; MCP mode is the one to take when the client has no shell access or when you want the tools visible in the client tool list.

   shell

   # what the skill mode actually runs
   ctx7 library next.js "middleware jwt cookies"
   ctx7 docs /vercel/next.js "middleware jwt cookies"

3. 3.Or wire the hosted server by hand

   There is no local server to run in the normal case: Context7 is a hosted endpoint at https://mcp.context7.com/mcp, and the API key travels as an Authorization: Bearer header. A free key from context7.com/dashboard mainly buys higher rate limits — anonymous use works until you cross a per-IP threshold, at which point the server fires an MCP elicitation asking you to sign in rather than silently degrading.

   mcp.json

   {
     "mcpServers": {
       "context7": {
         "type": "http",
         "url": "https://mcp.context7.com/mcp",
         "headers": {
           "Authorization": "Bearer YOUR_API_KEY"
         }
       }
     }
   }

4. 4.Add a rule so you stop typing "use context7"

   Out of the box you trigger it by appending use context7 to a prompt. ctx7 setup installs a skill that fires on library questions automatically; if you configured things manually, add the rule yourself — Cursor Settings then Rules, or CLAUDE.md for Claude Code. This is the single change that moves Context7 from a thing you remember to a thing that works.

   CLAUDE.md

   Always use Context7 when I need library/API documentation, code generation,
   setup or configuration steps without me having to explicitly ask.

5. 5.Name the library ID when you already know it

   Every question otherwise costs two calls: resolve-library-id to turn a name into an ID, then query-docs against that ID. Naming the ID in the prompt skips the first one. IDs look like /vercel/next.js, /supabase/supabase or /mongodb/docs. Versions work the same way — mention the version in the sentence and Context7 matches it, which is the entire point of the product.

   prompt

   Implement basic authentication with Supabase.
   use library /supabase/supabase for API and docs.

6. 6.Ask one concept per query

   A deliberate constraint rather than a style preference. The 3.2.3 release rewrote the query-docs description to tell callers to make a separate query per concept, because combining distinct topics in one query returns diluted, shallow results — the retrieval is a vector search, so a query spanning two subjects matches the middle of neither. The server also caps itself at three tool calls per question to stop an agent grinding through your context window.

   shell

   # instead of one query spanning both
   ctx7 docs /vercel/next.js "route handlers"
   ctx7 docs /vercel/next.js "middleware matcher config"

What it can do

Two MCP tools, and the small surface is the design. Both are read-only and carry the readOnlyHint annotation, so a client that surfaces tool safety will show them as non-destructive.

What people use it for

Which one should you use?

Context7 is a context source rather than a tool that does something to your project, so the real comparison is against the other ways docs reach the model.

Categories

Works With

Frequently Asked Questions