Product Plan & Specs
Five artefacts in one folder — the bridge between spec and sprint.
MVP Build Timeline · 8 Weeks
Happy Path First, End To End
Bar widths proportional to phase duration. Build the worst step first — day one, not Friday.
The Five Artefacts A Builder Ships From
Wireframes
Low-fi sketches for every screen on the critical journey. Name, one job, primary CTA, data on screen, next screen.
Excalidraw · 20 min sketch beats a 4-hr Figma
Screen Flow
One diagram from entry to outcome — including back-buttons, deep links, and the path after the primary action.
Mermaid · renders in GitHub, Notion, Markdown
System Flows
Data, auth, and payments — three one-page diagrams. Auth alone has seven steps most founders miss.
Supabase Auth · managed sign-up to session
Build Sequence + Cost
6-10 ordered slices, each demoable. In-week vs in-month MoSCoW cut. Anti-scope list: 3-5 explicit won't-haves.
Notion or plain Markdown in the repo
Repo Brief (CLAUDE.md)
The highest-leverage file you will write all week. Agent reads it every session. Under 400 lines — longer gets ignored.
Claude Code · persistent system prompt
The Artefact That Compounds
What The Product Is
Two paragraphs: who the user is, what the product does, the critical journey.
The Stack
Framework, auth, payments, DB, hosting — with versions. Vague versions produce vague code.
Architecture Rules
8-12 hard rules. "All transforms in Postgres RPC, never the frontend."
Where Things Live
Folder map. Agent finds the right file instead of inventing a new one.
Don'ts
6-10 sharp lines. Negative space is often more useful than positive.
When Unclear
One paragraph. "Check docs, then ask, never assume."