What Are Claude Skills? — AI Glossary

James Swierczewski

May 15, 2026

Claude Skills are reusable instruction packages that Anthropic introduced in early 2026. A Skill is a self-contained set of instructions, examples, and optional reference material that travels with you across conversations — once you have a Skill installed, Claude loads it automatically when the matching trigger appears in your prompt. Think of a Skill as a recipe that Claude remembers and applies on demand rather than something you re-explain every conversation.

Skills are designed for tasks that have specific conventions, output formats, or domain knowledge. Example uses: a brand-voice Skill that ensures Claude always writes in your company’s tone, a code-review Skill that applies your team’s standards, a customer-research Skill that runs a structured interview protocol. Skills are made up of a SKILL.md file (instructions and metadata) and optional supporting files. They can be installed via Claude.ai, Claude Code, or the API.

How Skills differ from related Claude features:

Skills vs. system prompts: A system prompt configures Claude for a single conversation. A Skill is installed once and applied across all conversations whenever its trigger matches.
Skills vs. Projects: Projects on Claude.ai contain conversation-specific context and files. Skills are portable instruction packages that work across projects and across Claude products.
Skills vs. plugins: Claude Code plugins are broader bundles that can include Skills, slash commands, agents, hooks, and MCP servers. A Skill is one building block; a plugin packages many together. See Claude Hooks and Plugins.
Skills vs. MCP: MCP (Model Context Protocol) connects Claude to external tools and data. Skills shape how Claude behaves on a task; MCP gives Claude access to outside systems. See What is MCP?.