Not a study list — a reference for the moment you hit one of these terms mid-task and want the plain-English version fast, not a spec document.
SkillA packaged set of instructions Claude Code loads to handle a specific recurring task the way you want it done, every time, without re-explaining yourself.
Full guide →HookA rule that runs automatically at a specific point (like every file edit) — automation that can't be talked out of enforcing itself, unlike an instruction in a config file.
Full guide →MCP (Model Context Protocol)How Claude Code connects to outside tools and services — a database, an API, a project management app — instead of you copy-pasting data between them manually.
Full guide →SubagentA separate context window for a piece of a larger task — used when a task is big enough that splitting the work actually helps, not by default.
Full guide →Plan ModeA step where Claude Code lays out its approach before touching anything — worth it for a task you don't already understand well, unnecessary overhead for one you do.
Full guide →MarketplaceA git repository with a specific file listing Skills or plugins you can browse and install from in one place — official or third-party, same underlying mechanism.
Full guide →CLAUDE.mdA file describing your project's conventions, constraints, and context — the equivalent of what you'd tell a new teammate on day one, given once instead of repeated every session.
Full guide →The free guide covers the fundamentals — you'll pick up these terms naturally as they become relevant, not before.
Get the Free Guide →No — most people start with none of them and pick each one up when it becomes relevant. This glossary is for when you hit a term mid-task and want the plain-English version fast, not a study list.
None of these, actually — the permission model is the concept that matters on day one. Skills, Hooks, MCP, and Subagents are all things you grow into after the fundamentals feel comfortable.
No — Plan Mode is a temporary mode for one task (think before acting). A Skill is a reusable, packaged capability you can invoke repeatedly across many tasks. Different tools for different problems.
A Hook reacts to something happening inside Claude Code itself (like enforcing a rule on every file edit). MCP connects Claude Code to something outside itself (a database, an API, another tool). One's internal automation, the other's external connection.