writing-plans

# Writing Implementation Plans ## Overview Write comprehensive implementation plans assuming the implementer has zero context for the codebase and questionable taste. Document everything they need: which files to touch, complete code, testing commands, docs to check, how to verify. Give them bite-sized tasks. DRY. YAGNI. TDD. Frequent commits. Assume the implementer is a skilled developer but knows almost nothing about the toolset or problem domain. Assume they don't know good test design very well. **Core principle:** A good plan makes implementation obvious. If someone has to guess, the plan is incomplete. ## When to Use **Always use before:** - Implementing multi-step features - Breaking down complex requirements - Delegating to subagents via subagent-driven-development **Don't skip when:** - Feature seems simple (assumptions cause bugs) - You plan to implement it yourself (future you needs guidance) - Working alone (documentation matters) ## Bite-Sized Task Granularity **Each task = 2-5 minutes of focused work.** Every step is one action: - "Write the failing test" — step - "Run it to make sure it fails" — step - "Implement the minimal code to make the test pass" — step - "Run the tests and make sure they pass" — step - "Commit" — step **Too big:** ```markdown ### Task 1: Build authentication system [50 lines of code across 5 files] ``` **Right size:** ```markdown ### Task 1: Create User model with email field [10 lines, 1 file] ### Task 2: Add password hash ...