A skill is a markdown file with frontmatter. The description decides when it loads, so it is written as a trigger condition rather than a summary. The same file works in Claude Code (~/.claude/skills/), on claude.ai under Settings → Capabilities, and committed into a repo for a whole team.
These are the ones I wrote. All free, all copy-paste, no packaging step.
source-finder
Mine
Returns the researchers, not the biggest channels.
When it fires
Any 'who should I read on X', any credibility check on a named person, and proactively before citing a popular figure in health, fitness, nutrition, longevity, finance or psychology.
Why it exists
Search ranks by reach, and reach correlates with production quality far more than with accuracy. This ranks by what kind of claim a source can actually support — six tiers, plus a disqualification pass that does most of the work.
Drafting or editing any prose a person will read, and whenever asked to make text sound less generic or less like AI wrote it.
Why it exists
LLM prose is recognisable because it is even — same sentence length, same rhetorical move every paragraph, a hedge before every claim. Human writing is lumpy. This removes the evenness and adds back the specificity. Explicitly not for disguising authorship of submitted work.
Course content that matches the evidence on how people learn.
When it fires
Writing a lesson, designing a quiz or exam, building review scheduling, choosing a progress metric, or reviewing existing course material.
Why it exists
The techniques that work feel worse than the ones that don't, so anyone building a course from intuition builds the wrong thing — and every competitor's marketing cites a learning pyramid whose source study has never been produced. This is the lesson shape, the question rules, the scheduling model, and an explicit do-not-build list, with the evidence behind each one.