ctx7 Official Documentation Lookup Guide

Why This Skill Exists

LLM training data contains outdated APIs, removed options, and behaviors that changed between versions. Relying solely on this knowledge leads to calling non-existent functions, using deprecated patterns, or generating code incompatible with the project's actual library versions. The result is wasted time debugging phantom issues and plans built on false assumptions.

ctx7 (context7 MCP) can query official documentation matching the exact version of libraries used in the current project. Work from facts, not guesses.

When NOT to Use ctx7

Do not look up documentation for APIs and patterns you are fully confident about. ctx7 lookups cost time and tokens. If the answer is obvious and the API is stable, just write the code.

Skip ctx7 when ALL of the following are true:

• The API is well-established and has not changed across recent major versions (e.g., useState, useEffect, fetch, Array.map, basic DOM APIs)
• You are fully confident in the exact signature, behavior, and usage pattern
• The task does not involve version-specific features, recent additions, or framework-level APIs that change between releases
• There are no special constraints in the task (e.g., "serverless", "edge runtime", "cross-instance") that might require a specialized variant