The body is lean and assumes Claude's competence — it presents methodology (the Discoverability Rule, Grey Box, three-question test) without padding or explaining basic concepts Claude already knows, and every section earns its place.

Concrete, executable guidance abounds: 'target <30 lines', 'If you're past 50 lines, it's bloated. Cut ruthlessly.', explicit belongs/does-not-belong lists, and 'Never duplicate between them'; templates and examples are delegated to real reference files.

The decision process is unambiguous and sequenced — apply the Discoverability Rule, then the three-question test as an explicit checkpoint, then write only what fails both — which fits the simple-skill allowance for a single, clear action.

Overview methodology lives inline while templates and the anti-pattern catalog are split into two real, one-level-deep references (anti-patterns.md, claude-md-guide.md), clearly signaled via a 'Deep Dives' table for easy navigation.

The lead capability statement 'Project documentation guidelines' is vague, but concrete actions (write documentation, create a CLAUDE.md, write a README, improve documentation) are enumerated through the trigger phrases, naming the domain and several actions without being comprehensive.

It explicitly answers what ('Project documentation guidelines') and when with an explicit 'Use when asked to...' clause enumerating multiple triggers, satisfying both halves.

Phrases like '"write documentation"', '"create a CLAUDE.md"', '"write a README"', '"document this project"', and 'creating/updating CLAUDE.md or README.md files' give good coverage of natural terms a user would actually say.

The triggers carve a clear niche around CLAUDE.md and README documentation work, making it unlikely to fire for unrelated skills despite the broad opening phrase.