21-Day Claude Code Challenge
A structured 21-day challenge that builds practical skills one day at a time. Learn Claude Code, GitHub, Plan Mode, and safer ways to review AI-assisted changes. The result is a learning project or first app version to test, not a guarantee of production readiness.
21-day roadmap + bonus week
Week 1
Install Claude Code
Install Claude Code and run your first prompt.
The 4-part prompt formula
Learn the formula that gets results every time.
Plan Mode
Make Claude think before it builds.
GitHub branch first
The one habit that saves everything.
Bounded automation
Use automation only inside clear boundaries, with review points before sensitive or large changes.
How to read error messages
Read errors without panicking.
Week 1 Build Day
A complete working homepage from scratch.
Week 2
The CLAUDE.md file
Give Claude permanent context for your project.
What to put in CLAUDE.md
The exact sections that make Claude smarter.
Slash commands
Shortcuts that save you time every session.
The @mention trick
Point Claude at exactly the right file.
Multi-clauding
Run multiple Claude sessions at the same time.
When AI goes wrong
How to recover when Claude breaks things.
Week 2 Build Day
Build a complete second feature from scratch.
Week 3
Skills
Teach Claude your workflow so you never repeat yourself.
Create your own skill
Build a custom skill for your exact project.
Plan Mode for big builds
Use Plan Mode before any complex change.
The loop command
Understand when repeated iteration is useful, and when you need to pause and inspect the work.
Sub-agents
Use specialist tasks with boundaries and review before they touch sensitive areas.
Pre-session workflow
The 5-minute habit before every build session.
Review and next steps
Review what works, what was tested, and what remains unknown before deciding whether to continue.
Bonus Week — Advanced Skills
What hooks are and how to add one safely
Inspect your real hook setup, add one safe notification hook, and verify it without guessing.
The context window — why Claude goes weird and how to fix it
Spot the warning signs of a full context and fix it in seconds with /compact.
The 5 Golden Rules — the checklist every session needs
Five rules that consistently produce better results and fewer mistakes.
What MCP is and how to inspect or add one connection safely
Inspect existing MCP access, add one safe read-only connection, and verify it before trusting it.
Subagents — how to give Claude Code a specialist job title
Create a reviewer subagent that checks your site through specialist eyes.
Basic safety rules before you let AI touch your files
Five safety rules every non-developer must know before running an AI session.
How to read a diff — and why you must before accepting any change
Read a diff in 30 seconds, catch unexpected changes, and revert only what you did not want.
Use Claude Code inside boundaries
Claude Code is powerful, but it can make unsafe assumptions. Use Plan Mode or an audit-first prompt before large edits, commit before major changes, and review the diff before accepting work.
- Do not let autonomous or long-running work touch sensitive areas without review.
- A passing command is not proof that the full app works; verify what changed, what was tested, and what remains unknown.