Context7 Lookup

Context7 Lookup

Context7 is an MCP server that injects up-to-date, version-specific documentation directly into your context. Use it to avoid hallucinated APIs and outdated code examples.

What This Skill Is

This skill teaches you how to use Context7 MCP tools effectively. It does not replace Context7 — you must have Context7 MCP configured in OpenCode.

When to Use Context7

• Before implementing code with external libraries/frameworks
• When unsure about current API signatures
• For fast-moving libraries: Next.js, React, Vue, Tailwind, Zod, etc.
• When the user asks about a specific library version
• When you see "use context7" in a prompt

Prerequisites: Configure Context7 MCP in OpenCode

Add to your opencode.json:

Remote Server Connection (Recommended)

{
  "mcp": {
    "context7": {
      "type": "remote",
      "url": "https://mcp.context7.com/mcp",
      "headers": {
        "CONTEXT7_API_KEY": "YOUR_API_KEY"
      },
      "enabled": true
    }
  }
}

Local Server Connection

{
  "mcp": {
    "context7": {
      "type": "local",
      "command": ["npx", "-y", "@upstash/context7-mcp", "--api-key", "YOUR_API_KEY"],
      "enabled": true
    }
  }
}

Get a free API key at context7.com/dashboard for higher rate limits.

Available Tools

Once Context7 MCP is configured, you have access to two tools:

1. resolve-library-id

Resolves a library name to a Context7-compatible ID.

Always call this first unless the user provides an explicit ID like /vercel/next.js.

Input: "next.js"
Output: "/vercel/next.js" (with version info)

2. get-library-docs

Fetches documentation for a library.

Usage Pattern

1. User asks about implementing something with a library
2. Call `resolve-library-id` with the library name
3. Call `get-library-docs` with the resolved ID and relevant topic
4. Use the returned documentation to provide accurate code

Examples

Example 1: Next.js Middleware

User: "Create a Next.js middleware for auth"

Agent:

1. resolve-library-id("next.js") → /vercel/next.js
2. get-library-docs("/vercel/next.js", topic="middleware") → Current middleware docs
3. Provide code based on actual current API

Example 2: Specific Topic

User: "How do I invalidate queries in TanStack Query?"

Agent:

1. resolve-library-id("tanstack query") → /tanstack/query
2. get-library-docs("/tanstack/query", topic="invalidation") → Current invalidation patterns
3. Provide accurate queryClient.invalidateQueries() usage

Example 3: Known Library ID

User: "Implement auth with Supabase. use library /supabase/supabase"

Agent:

1. Skip resolve-library-id (ID already provided)
2. get-library-docs("/supabase/supabase", topic="authentication")
3. Provide code based on current Supabase auth API

Tips

• Be specific with topics: topic="authentication" returns more relevant docs than a general query
• Use slash syntax: If you know the library ID, use /org/project directly
• Trust the docs: Prefer Context7 results over training data for API signatures
• Don't over-fetch: If you've already fetched docs for a library in this conversation, reuse them

Supported Libraries

Context7 supports 1000+ libraries. Check context7.com for the full list.

Popular ones include: React, Next.js, Vue, Nuxt, Svelte, Angular, Express, Fastify, NestJS, Django, FastAPI, Prisma, Drizzle, Tailwind, Zod, TanStack Query, and many more.

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