plan-first-developmentlisted

# Plan-First Development Break complex projects into detailed multi-phase plans before writing any code. Prevents scope creep, refactoring waste, and missed requirements. ## When to use - Starting any project with >1000 lines of code - Building systems with multiple interacting components - Performance-critical applications (HFT, real-time, embedded) - Projects where requirements are complex but knowable upfront - When multiple developers need coordination ## When NOT to use - Exploratory prototypes where requirements are unknown - Trivial scripts (<100 lines) - Already well-understood patterns (CRUD apps) - Research projects where discovery is the goal ## Instructions ### Step 1: Define Project Scope Create a project overview document with: ```markdown # [Project Name] - Implementation Plan ## Overview [2-3 sentence description] ## Core Constraints - ❌ [What we CANNOT use/do] - ✅ [What we MUST use/do] ## Success Criteria - [ ] [Measurable outcome 1] - [ ] [Measurable outcome 2] - [ ] [Performance target, if applicable] ``` ### Step 2: Break Into Phases Divide project into 5-10 sequential phases. Each phase should: - Build on previous phases (dependencies clear) - Have concrete deliverable (working code + tests) - Take 1-4 hours to complete - Be independently testable **Template:** ```markdown ### Phase N: [Component Name] **Objective**: [What are we building?] **Files to create:** - `path/to/file1.ext` - [Purpose] - `path/to/file2.ext` - [Purpose] **Key imp