Context7

What it does

Serves version-specific documentation for thousands of libraries, so an agent stops writing code against an API that changed two releases ago. The practical fix for hallucinated function signatures. Free tier is generous enough for individual use.

Install

npx -y @upstash/context7-mcp

Client configuration

Paste this into your MCP client config (Claude Desktop, Cursor, or any client that reads mcpServers), then restart the client.

{
  "mcpServers": {
    "context7": {
      "command": "npx",
      "args": [
        "-y",
        "@upstash/context7-mcp"
      ]
    }
  }
}

When to use it

Reach for this when the task needs docs inside the agent loop. Skip it if a plain shell command or a one-off script is enough — every server you add costs context and adds a failure mode.

Other TypeScript servers

• Filesystem — Gives an agent scoped read, write, and search access to directories you explicitly allow
• Memory — A persistent knowledge graph stored in a local JSON file, exposed through entities, relations, and observations
• Sequential Thinking — Gives the model a scratchpad for structured, revisable reasoning: numbered thoughts that can branch, revise, and conclude