source: kdnuggets: anthropic’s complete guide to claude skills building
level: technical
a claude skill is a folder containing a required skill.md file and optional directories for scripts, references, and assets. it embeds your preferences, workflows, and domain knowledge so claude loads them automatically when the task matches. skills use a three-level progressive disclosure system: yaml frontmatter always loads in the system prompt, the skill.md body loads when relevant, and referenced files load only as needed. this keeps context usage low even with many skills installed.
before writing, define two or three concrete use cases with triggers, steps, and expected results. common categories are document creation, workflow automation, and mcp enhancement. set success criteria like triggering on 90% of relevant queries. the technical rules are strict: the file must be named skill.md exactly, folder names use kebab-case, and no readme inside the skill folder. the frontmatter description must include what the skill does and when to use it, or claude won't activate it reliably.
write the main instructions in markdown with clear steps, examples, and troubleshooting. be specific with commands and expected outputs, handle errors, and reference bundled files by path. keep the core file focused and move detailed docs to references/. test against your success criteria and distribute via github, ensuring the human-readable readme is at the repository root, not inside the skill folder.
why it matters: skills let data scientists and developers stop re-pasting context into every claude chat, making repeatable ai-assisted work faster and more consistent.
source: kdnuggets: anthropic’s complete guide to claude skills building