Design OS

Incremental Implementation

Build your product section by section for more control and easier review.

For larger products or when you want to review progress incrementally, this approach lets you build one section at a time.

How It Works

Work through the instructions in order:

  1. Foundation (instructions/incremental/01-foundation.md) — Design tokens, data model types, routing
  2. Shell (instructions/incremental/02-shell.md) — Application shell and navigation
  3. Sections (instructions/incremental/03-*.md, 04-*.md, etc.) — Each feature section, one at a time

For Each Milestone

  1. Open product-plan/prompts/section-prompt.md
  2. Fill in the section variables at the top (SECTION_NAME, SECTION_ID, NN)
  3. Add any section-specific notes
  4. Deliver the prompt to your coding agent in Plan mode
  5. Answer clarifying questions, then give the go-ahead to implement
  6. Review and test before moving to the next milestone

Why Plan Mode?

Plan mode encourages the agent to analyze the instructions thoroughly, ask clarifying questions, and build a complete implementation plan before writing code. This catches issues early and ensures the plan works for your codebase.

The Section Prompt

The section prompt is designed to give your agent everything it needs:

  • References the section's instruction file and assets
  • Points to tests.md for test-driven development
  • Asks about auth, data relationships, and integration points

Benefits of Incremental Implementation

  • Easier review — Review and test each section before moving on
  • Catch issues early — Problems are contained to a single section
  • Better control — You decide when each section is ready
  • Flexible pacing — Take breaks between sections as needed

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