What each spec document contains, why it exists, and lean templates for solo dev + AI workflows.

Project Charter

Purpose: Establish the why and boundaries of the project in one page.

Required sections:

• Problem Statement — What pain exists and for whom
• Vision — One-sentence target state
• Scope — IN (what you will build) / OUT (what you won’t)
• Success Criteria — 3–5 measurable outcomes
• Constraints — Technical, resource, or timeline limits

Template skeleton:

# Project Charter: {Name}
Version: 0.1.0 | Date: YYYY-MM-DD | Status: Draft

## Problem Statement
{1–2 paragraphs}

## Vision
{1 sentence}

## Scope
### In Scope
- ...
### Out of Scope
- ...

## Success Criteria
1. {Measurable outcome}
2. ...

## Constraints
- ...

PRD (Product Requirements Document)

Purpose: Define what to build with enough detail that acceptance criteria are unambiguous.

Required sections:

• User Personas — Who uses this and how
• Requirements — Grouped by priority (P0/P1/P2)
• Acceptance Criteria — For each P0 and P1 item
• Non-Functional Requirements — Performance, limits, compatibility