Lesson 03

Build with Claude Code and close the loop.

Use the gather-context, act, and verify loop, with a runnable check that lets the agent correct its own work.

Suggested time: 15 minutes to set up · 60–120 minutes to build
You will finish with: A small implementation verified against an explicit user journey.

Authenticate deliberately

Claude Code supports subscription login for eligible plans and API-based access. Environment API keys take precedence when present.

Follow your organization’s approved login method.
Check the active authentication context before working in a sensitive repository.
Keep credentials outside prompts, commits, screenshots, and logs.

Let the agent inspect first

Ask it to read the relevant files and explain the planned slice before broad changes.

Start with exploration for unfamiliar code.
Keep implementation bounded to the stated journey.
Commit only after the runnable verification succeeds.

Give it a correction signal

Tests and browser observations are feedback the agent can act on.

Provide the exact failing command or reproduction.
Require it to rerun the same check after editing.
Inspect console, network, empty states, and keyboard navigation yourself.

Copy-ready starter prompt

Replace the bracketed details, give it to your coding agent, and keep the verification steps intact.

Explore this repository and identify the smallest vertical slice for [FEATURE]. Read its instructions and relevant tests first.

Plan the journey [START] → [ACTION] → [RESULT], then implement it without expanding scope. Preserve unrelated work and do not add external services, secrets, trackers, or remote assets.

Verify with the repository’s real test, typecheck, lint, and production-build commands. Exercise the journey in a browser at desktop, 390px, and 320px; inspect keyboard focus, console errors, and external requests. Fix observed failures and return the exact evidence plus any incomplete checks.

Official resources

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