1In one sentence
Helpers split big jobs between several Claudes, hooks run your checks automatically at set moments, and plugins package all of it so a team installs it in one go.
2New words
- Helper (Anthropic: sub-agent) — a separate Claude with its own notes and tools that handles one part of a task (explore the code, plan, review) and reports back. Chapter 2.5 showed them in Cowork; in Claude Code you can define your own.
- Hook — a small rule: "when X happens, run Y". For example: after every file change, run the tests; before any command that deletes, ask me. Hooks fire automatically.
- Lifecycle event — the moments a hook can attach to: a session starting, a tool about to run, a tool having run, Claude finishing.
- Plugin — a package of skills, helpers, hooks and connectors, installed from a marketplace or a folder.
3Why you would want it
Rules in CLAUDE.md depend on Claude remembering them. Hooks do not: the tests run after every change whether or not Claude thought of it. Helpers keep the main session clean while a reviewer-helper reads the whole change with fresh eyes. Plugins mean a new team member gets the same setup in one command.
4Try it now
(Claude Code, paid plans)
- Ask Claude Code: Add a hook that runs our tests after every file edit and shows me failures. It writes the setting; read it before accepting.
- Ask: Create a helper called reviewer that only reads files and reports problems, never edits. Then use it to review the last change.
- Browse the plugin marketplace (type /plugin) and install one that matches your work.
5What you will see
[Picture pending: a hook firing after an edit, and a helper's report.] After the hook is in, every edit is followed by a test run in the session, with failures shown. The reviewer helper returns a short list of problems, and the main session stays readable. Installed plugins add their skills to the / menu.
6Watch out
- A hook that fails blocks the work by design. Test it on a small change first.
- Helpers cost more of your limit; use them for review and exploration, not for every message.
7Go further
Combine them: a hook that triggers the reviewer helper before anything is committed. Chapter 6.5 connects Claude Code to the tools and data outside your folder.