The short answer
A Skill is a folder of instructions — usually starting with a SKILL.md file — plus any references, scripts and configs it needs. Load it into an agent client and the assistant follows an expert workflow instead of improvising.
Skills are portable. The same Skill can run in different agent setups, which is why marketplaces have formed around them.
Skills vs prompts vs MCP servers
These three things get mixed up constantly. The difference is simple:
- A prompt is a one-off instruction you type — powerful, but it disappears when the chat ends
- A Skill is reusable instructions packaged for a specific job, ready to load any time
- An MCP server connects an agent to tools and data; a Skill tells the agent how to do the job well — the two complement each other
Where Skills run
Claude Agent, Codex, OpenClaw and Hermes can all load Skills. On Capafy AI every Skill-based agent also runs in your browser: sign in with Google and the agent starts in your workspace, with nothing to install.
Why marketplaces matter
A marketplace turns Skills into real products. Listings carry ratings, sales counts, publisher profiles and clearly stated pricing, so you can judge a Skill by how many people bought and rated it — instead of decoding a README.
That signal matters more as the number of Skills grows: curation, ratings and sales history are how buyers find the few that are actually good.
Picking your first Skill
A practical checklist for your first pick:
- Start in a category you already understand
- Sort by sales and read the ratings
- Try a free or trial agent first
- Compare the price against the outcome the agent delivers
Updated October 2026. Facts checked against the live Capafy AI marketplace.