Module 4: Vibe Coding4.2: Plan

4.2: Plan

  • Time to Complete: 20-25 minutes

Interactive lesson: Run /start-4-2 in Claude Code

In this lesson: Claude interviews you to create a requirements spec.

What Are Requirements?

Requirements are a description of what you’re building before you build it.

Think of it as the “contract” between you and whoever builds it. The more detail upfront, the fewer surprises later.

This principle applies whether you’re working with:

  • AI tools
  • Developers
  • Designers
  • Agencies

Vague instructions = unexpected results. Specific requirements = what you actually wanted.

What is “Logic” in Software?

Logic is the rules for how something behaves. It’s the “if this, then that” layer.

Every app has logic:

  • If user clicks button → show next screen
  • If answer = A → add point to personality X
  • If score is highest → show that result

You define the logic in plain English. Claude implements it in code.

How Recommendation Engines Work

Quizzes, product recommenders, and matchmakers all use the same pattern:

  1. User inputs → answers, preferences, choices
  2. Scoring system → each input adds weight to outcomes
  3. Output → highest scoring outcome wins

For a personality quiz:

  • Each answer maps to a personality type
  • Answers accumulate points
  • Final result = personality with most points

You don’t code this - you just decide the mappings.

Why Visual Previews Matter

Words are ambiguous. “Modern” means different things to different people.

Seeing options is faster than describing preferences. You know it when you see it.

Claude can generate HTML preview files with different visual styles and open them in your browser. You pick what you like - or mix elements from multiple options.

The REQUIREMENTS.md File

At the end of this lesson, all your decisions get saved to a single file: REQUIREMENTS.md

This includes:

  • What you’re building
  • The logic (how it works)
  • Visual style preferences
  • Content (questions, results, etc.)

This file is the spec Claude builds from in the next lesson.

What’s Next

4.3: Build & Iterate → - Watch Claude build your app, then refine it until you love it

4.1: Setup4.3: Build & Iterate