Claude Code: skills vs subagents vs commands

Claude Code is customized through a handful of config types. They are easy to mix up, so here is what each one is and when to reach for it.

The config types

Skill

A SKILL.md file that teaches a repeatable capability or procedure. Uses the open agentskills.io format, so it is portable across Claude Code, Codex, Cursor, Gemini CLI and more.

When to use: Claude auto-invokes it when the task matches.

Subagent

A specialized sub-assistant with its own prompt, tools and separate context window (e.g. a code-reviewer or test-writer).

When to use: Delegate a well-scoped task so it does not clutter your main context.

Slash command

A reusable prompt or workflow you trigger with /name.

When to use: One-shot, on-demand actions you run yourself (e.g. /review).

Hook

A shell command that fires on lifecycle events (PreToolUse, PostToolUse, Stop, ...).

When to use: Deterministic automation — format on save, block risky commands, run tests.

CLAUDE.md

Project or user memory: conventions, do/don'ts and context injected every session.

When to use: Encode house rules so you do not repeat them each time.

MCP server

A Model Context Protocol connection to external tools and data.

When to use: Give Claude live access to your DB, APIs, docs or design tools.

FAQ

Is a skill the same as a subagent?

No. A skill is a portable instruction file Claude loads when relevant; a subagent is a separate assistant with its own context and tools. Skills are cross-tool (agentskills.io); subagents are a Claude Code feature.

Should I use a slash command or a subagent?

Use a slash command for a quick action you trigger yourself. Use a subagent when you want to delegate a whole task in an isolated context.

Where do these files live?

In your project or home .claude/ folder (agents/, skills/, commands/), plus CLAUDE.md and hooks in settings. ConfigDeck installs them there in one click.

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