Context7

Retrieve current documentation for software libraries by querying the Context7 API. This is especially useful when you're unsure about an API's current interface — library docs change frequently and your training data may be outdated.

Requires CONTEXT7_API_KEY environment variable.

When to Use

• Looking up how a library function works (e.g., "how does useEffect cleanup work?")
• Checking if an API has changed in a newer version
• Finding code examples for a specific library feature
• Verifying correct import paths or function signatures
• Installing or configuring a library and needing setup docs

When NOT to Use

• General programming questions (e.g., "how do closures work in JS?")
• Questions about your own project's internal code
• Topics unrelated to a specific open-source library or framework

Workflow

DO NOT read script source code. Run scripts directly and use --help for usage.

Step 1: Search for the Library

python3 scripts/context7.py search <library> <topic>

Returns TSV with top 5 matches: id, title, snippets. Use the id from the best-matching row for the fetch step.

Step 2: Fetch Documentation

python3 scripts/context7.py fetch <library_id> <topic> [--max-tokens N]

Fetches documentation snippets relevant to the topic, truncated to a token budget (default: 5000).

Choosing --max-tokens:

Run python3 scripts/context7.py --help for full usage.

Examples

# Find React library ID, then fetch useState docs
python3 scripts/context7.py search react "useState hook"
python3 scripts/context7.py fetch /websites/react_dev "useState hook with objects"

# Smaller budget for a quick lookup
python3 scripts/context7.py fetch /vercel/next.js "middleware redirect" --max-tokens 2000

# Broader exploration
python3 scripts/context7.py fetch /langchain-ai/langchainjs "retrieval chain setup" --max-tokens 8000

Rules

• Write specific queries — "useState hook with objects" retrieves much better results than "hooks", because the API ranks snippets by relevance to your query.
• Always search before fetching — Library IDs aren't guessable (e.g., /websites/react_dev), so you need the search step to find the right one.
• Match --max-tokens to the task — Use the table above. Overshooting wastes context window; undershooting may miss the answer.