051-design-two-steps-methods

# Two-Step Change Method Guide Java developers through complex or risky changes by keeping design preparation separate from behavior modification. **This is an interactive SKILL**. **What is covered in this Skill?** - Clarifying the intended behavior change before editing - Identifying design obstacles that make the change difficult or risky - Step 1: behavior-preserving preparatory refactoring that makes the change easy - Validation that Step 1 preserves existing behavior - Step 2: the smallest intended behavior change after the design supports it - Verification that Step 2 delivers the intended behavior - Handoff to focused Java, framework, persistence, messaging, API, or testing skills while preserving the two-step sequence ## Constraints Separate behavior-preserving preparation from behavior-changing work, and validate after each step. - **MUST**: State the intended behavior change before proposing preparatory refactoring - **MUST**: Keep Step 1 behavior-preserving; do not mix broad refactoring with the intended behavior change - **MUST**: Verify existing behavior after Step 1 using the project-appropriate tests, build, characterization tests, or manual checks - **MUST**: Make Step 2 only after the design has been prepared and validated - **MUST**: Verify the intended behavior after Step 2 with focused tests and relevant build checks - **MUST**: Record assumptions and risks when preparation cannot be fully separated from behavior change ## When to use this skill -...