Simple explanation
Welcome to Day 20. Tomorrow is your final build day. Today you prepare for it — and for every session after this challenge ends. Why a pre-session ritual matters Every session you start without a ritual costs you time. You open Claude Code. You realise you forgot to create a branch. You start typing a prompt. You realise you forgot to update CLAUDE.md with today's goal. Claude Code builds the wrong thing. You start over. A pre-session ritual takes 3 minutes. It eliminates an hour of mistakes. The best builders do the same things in the same order before every single session. Not because they are rigid. Because consistency is the fastest workflow. Your personal pre-session checklist — the baseline Before opening Claude Code: Step 1 — Write your one-task brief On paper or in a notepad — write one sentence: what is the single thing I want to exist at the end of this session that does not exist now? Not a list. One thing. Step 2 — Update CLAUDE.md Open your CLAUDE.md file. Update the Current Goal section with today's one task. Check that your design rules and no-go zones are still accurate. Step 3 — Create a branch Open GitHub Desktop. Create a new branch named after today's task. Example: adding-faq-page or fixing-mobile-layout.
What to do
When you open Claude Code: Step 4 — Choose your mode Simple one-file task — normal mode. Complex multi-file task — Plan Mode first. Long autonomous task — Auto Mode with a branch ready. Step 5 — State your context first Begin every first prompt with: "Following all rules in CLAUDE.md — today's task is [your one-sentence brief]." After your session: Step 6 — Run /review Before merging anything — type /review and ask Claude Code to check the work. Step 7 — Test it yourself Open your site in the browser. Click every new thing. Fill in every form. Look at it on your phone. Step 8 — Merge or discard If it works — merge to main. If not — identify the problem, fix it, then merge. Step 9 — Commit with a clear message In GitHub Desktop — write a commit message that describes what you built. Not "update" — useless later. "Added FAQ page with 8 questions and accordion layout" — useful forever. Saving your ritual as a Skill Ask Claude Code to create a /session-start Skill: "Create a Skill called session-start. When triggered it should: remind me to update CLAUDE.md, ask me for today's one-task brief, confirm I have created a GitHub branch, and ask which mode I want to work in today." Today's practical task 1. Write your personal pre-session checklist — adapted from the baseline above. 2. Create the /session-start Skill. 3. Run through the complete checklist once today — even for a simple task. 4. Notice how much more focused the session feels when you start with a clear single goal. 5. Keep the checklist somewhere permanent — a note app, a printed card, whatever you will actually use.
Copy-paste prompt
Create a Skill called session-start that I can trigger with /session-start. When triggered it should walk me through my pre-session ritual: first ask for today's one-task brief in one sentence, then remind me to update CLAUDE.md with that goal, then confirm I have created a GitHub branch named after the task, then ask which mode I want (normal, plan, or auto), and finally confirm it is ready to begin. Save this to .claude/skills/session-start.md
Course note
Key takeaway
One task. CLAUDE.md updated. Branch created. Mode chosen. Context stated. Those five things before every session eliminate the most common hour-wasting mistakes. Save them as a /session-start Skill and run it automatically from tomorrow.