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when you're unsure about an API's current interface — library docs change frequently and your training data may be outdated.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:

Scenario	Tokens	Why
Quick lookup (one function signature)	2000	Keeps output focused, faster response
Typical usage (API patterns, examples)	5000 (default)	Good balance of depth and brevity
Broad exploration (migration guide, full API surface)	8000–10000	Needed when topic spans multiple sections

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.