looking-up-docs

Library documentation via Context7. Use for API references, code examples, framework docs.

allowed_tools: Read, Grep, Glob, mcp__context7__resolve-library-id, mcp__context7__query-docs

$ インストール

git clone https://github.com/alexei-led/claude-code-config /tmp/claude-code-config && cp -r /tmp/claude-code-config/skills/looking-up-docs ~/.claude/skills/claude-code-config

// tip: Run this command in your terminal to install the skill


name: looking-up-docs description: Library documentation via Context7. Use for API references, code examples, framework docs. allowed-tools:

  • Read
  • Grep
  • Glob
  • mcp__context7__resolve-library-id
  • mcp__context7__query-docs

Documentation Lookup with Context7

Context7 provides up-to-date, version-specific documentation and code examples directly from source libraries.

Why Context7

  • Current APIs: No hallucinated or outdated patterns
  • Version-specific: Gets docs for exact library versions
  • Code examples: Real, working code from actual documentation

Workflow

  1. Resolve library ID: mcp__context7__resolve-library-id with libraryName
  2. Get documentation: mcp__context7__query-docs with context7CompatibleLibraryID and topic

Modes

ModeUse For
codeAPI references, code examples (default)
infoConceptual guides, architecture, tutorials

Examples

# React hooks
resolve-library-id: "react"
get-library-docs: context7CompatibleLibraryID="/facebook/react", topic="hooks", mode="code"

# Next.js middleware
resolve-library-id: "next.js"
get-library-docs: context7CompatibleLibraryID="/vercel/next.js", topic="middleware"

# Go net/http
resolve-library-id: "go net/http"
get-library-docs: context7CompatibleLibraryID="/golang/go", topic="http server"

# Kubernetes API
resolve-library-id: "kubernetes"
get-library-docs: context7CompatibleLibraryID="/kubernetes/kubernetes", topic="deployment"

Tips for Better Results

Be specific with queries:

  • BAD: topic="hooks" → returns everything hook-related
  • GOOD: topic="useEffect cleanup function" → precise results

Filter strategies:

  • Use topic with function/method names: topic="json.Unmarshal"
  • Include version when relevant: libraryName="react 18"
  • Combine with feature context: topic="middleware error handling"

When results are too broad:

  1. Narrow the topic parameter
  2. Try mode="code" to focus on examples
  3. Paginate: page=2, page=3 for additional results
  4. Re-resolve library ID with more specific name

Quality check:

  • Verify code examples match your library version
  • Cross-reference with official docs if uncertain

Fallback: Empty or Missing Results

When Context7 returns no results or doesn't have the library:

Decision Tree

Context7 query returns empty?
├── Try broader query (e.g., "hooks" instead of "useCallback")
├── Still empty?
│   ├── Re-resolve library ID with alternative name
│   │   (e.g., "nextjs" → "next.js", "golang" → "go")
│   └── Still empty?
│       ├── Library not indexed → Use fallbacks below
│       └── Very niche library → WebSearch for official docs

Fallback Strategies

  1. Alternative library ID: Try variations

    # If "fastapi" fails, try:
    resolve-library-id: "starlette"  # FastAPI's underlying framework
    resolve-library-id: "pydantic"   # Often used with FastAPI
    
  2. WebSearch for official docs:

    WebSearch: "<library> official documentation <feature>"
    WebFetch: Official docs URL → extract relevant info
    
  3. Source code exploration (for open-source):

    # Clone and explore
    git clone --depth=1 <repo>
    Grep: "function <name>" --type=<lang>
    
  4. Perplexity for recent/niche libraries:

    mcp__perplexity-ask__perplexity_ask: "How to use <feature> in <library> 2024"
    

Libraries Commonly Not in Context7

LibraryFallback
Internal/proprietarySource code + README
Very new (<6 months)WebSearch + official docs
Niche/specializedPerplexity or GitHub issues
Language stdlibUse language docs directly

Example Fallback Flow

# Initial attempt fails
resolve-library-id: "htmx"
→ No results

# Fallback 1: WebSearch
WebSearch: "htmx documentation hx-swap"
→ Found: https://htmx.org/docs/

# Fallback 2: Fetch docs
WebFetch: url="https://htmx.org/docs/", prompt="Explain hx-swap attribute"
→ Returns relevant documentation

When to Skip Context7 Entirely

  • Asking about breaking changes between versions → WebSearch release notes
  • Debugging specific error messages → WebSearch + StackOverflow
  • Comparing libraries → Perplexity for analysis
  • Very recent features → WebSearch for latest docs