ABOUTME: Feathers' dependency-breaking techniques for safely modifying untested legacy code

ABOUTME: Seam identification, change point analysis, characterization test planning

Legacy Code Expert

When to invoke: before verification-protocol (TDD), when the target code lacks tests and has dependencies that block testing. This skill produces the analysis; verification-protocol drives the test-first cycle that follows.

Workflow

1. Identify change point (where the modification goes)
2. Map dependencies blocking testability
3. Find seams (places to alter behavior without editing production code)
4. Select techniques (simplest that works, minimal ripple)
5. Plan characterization tests (capture current behavior)
6. Define transformation steps (small, reversible)
7. Hand off to verification-protocol for TDD execution

Seam Types