Lesson 06 · Claude Mastery Pro+ ~16 min Interactive · for developers

Claude Code: the CLI for real work.

Claude Code is Anthropic's command-line tool that gives Claude direct access to your codebase, terminal, and file system. It's the most capable AI coding tool there is — and the riskiest if you let it off the leash. This lesson covers setup, MCP servers, and the review discipline that makes it safe: the patterns that ship code instead of breaking things.

Step 1 of 50% complete

The mental model

Not an autocomplete — a junior who runs commands

Claude Code can read your code, write code, run tests, search the web, and make commits. The difference from Copilot or Cursor is autonomy: it does multi-step work and reports back. Which means the way you use it well looks less like coding and more like managing.

Predict first

What's the right way to think about Claude Code?

Setup & what it does

Install once, then delegate

npm install -g @anthropic-ai/claude-code → run claude in any repo

① Start with low-stakes tasks

Docs, tests, small refactors, codebase Q&A. Ask for a diff before it commits.

"Add JSDoc to every public function in src/utils, run the tests, show me the diff before committing."

② Connect your tools via MCP

GitHub, Linear, Postgres — so it can read issues, query schemas, and see PR context.

Use read-only credentials for any production system — never give it write access to prod.

③ Multi-step feature work

Hand it a brief; it plans, codes, tests, and preps the PR — with you reviewing at checkpoints.

"Plan first, show me, then execute step by step. Ask before destructive operations."

Two rules that prevent most disasters: require a plan first on anything multi-step, and never let it commit-and-push in one shot — review the diff yourself.

Do it · review the plan

You're the senior. Approve or flag each step.

You gave Claude Code a brief and asked it to plan first. Here's its plan. Approve the steps that fit the brief; flag the ones that don't or that need a human first.

claude > here's my plan

Brief: Add PATCH /users/:id/delete (sets deleted_at, returns 204), update the User model, add a migration, write unit tests, update the API docs. Don't change existing endpoints. Ask before destructive operations.

The discipline

The senior reads the diff

Claude Code finishes the feature, tests pass, and it offers to commit and push to main in one step to save you time.

The call

What's the right move?

⌨️

Lesson complete

You can delegate to Claude Code — and stay the reviewer

What you can do now

Install Claude Code and run your first low-stakes task
Connect your tools via MCP — with read-only creds on anything production
Require a plan first on any multi-step work
Review the plan and the diff like a senior reviewing a junior
Never commit-and-push in one shot; open a PR you can read

Your move: ship one thing with Claude Code

Pick a small feature or chore in your current project. Run it end-to-end — brief, plan, code, test, PR — and review carefully. Notice which parts saved time and which needed your full attention. That calibration is the real skill.

Try a prompt in the playground →

Pro

Up next in Claude Mastery

Custom instructions: teach Claude your style once

How to write custom instructions that genuinely change the output — the four sections every good instruction set needs, and the anti-patterns that make Claude worse.

Continue to Custom instructions → Back to all lessons