CatalogueThe reference for the Agent Skills format
How Claude skills work, field by field
A skill is a folder of instructions an agent loads when a task matches its description. This site documents the format itself: what SKILL.md may contain, what the constraints really are, how loading is staged, and how skills interact once several are installed.
SKILL.md reference6Frontmatter fields
14Conflicts and pairings
4Publisher
30Skills
01What is a skillA skill is a folder of written instructions that an agent loads when the task in front of it matches the skill's description. It is not a plugin, not a model and not an integration. This page explains the parts, and what decides whether a skill helps or gets ignored.↗02SKILL.md referenceA skill is a directory with a SKILL.md file at its root. This page lists what that file may contain, quoted from the specification rather than inferred from examples, so you can check a skill against it line by line.↗03Write your first skillA skill is a folder with a SKILL.md file in it. This guide builds one real skill end to end, and stops at each point where a decision is easy to get wrong. It assumes nothing except that you have a workflow you have already done by hand more than once.↗04Skill generatorFill in what the skill does and when it should be used, and this builds a SKILL.md that passes the specification's rules. The description is composed for you in the shape the spec asks for, because a missing when clause is the most common reason a finished skill never loads. Everything runs in your browser.↗05Description checkerThe description is what decides whether a skill is ever loaded. This checker runs the specification's hard constraints against your name and description, then adds the triggering heuristics that separate a description an agent can match from one it will ignore. Everything runs in your browser.↗06TroubleshootingSkills fail quietly. Nothing errors, nothing is logged, and the agent simply behaves as though the skill is not there. This page starts from what you can actually observe and works back to the cause.↗
Conflicts and pairings
Two of the most recommended skills here conflict with each other. The map shows which pairs collide and which ones cover each other's gaps.
See conflicts and pairingsPublisher
Sources
All constraints on this page come from the published specification, read on the date shown. Check the source before relying on a field in production.
Agent Skills specification