Claude Code design-legacy-seams skill: Characterize behavior before refactoring
Find a small seam for a clock, service, or global dependency. Record the existing behavior with focused tests before changing the implementation.
中文Install in Claude Code
Work in a local Claude Code practice project. A controllable date is enough for the example.
- Download the repository snapshot at the linked commit. Copy software-design-plugin/skills/design-legacy-seams/ into .claude/skills/design-legacy-seams/ in your practice project and keep its reference files.
- Check that SKILL.md is directly inside .claude/skills/design-legacy-seams/. Open Claude Code from the project root.
- Enter /design-legacy-seams to try the example below.
Example task
Run /design-legacy-seams with a library reminder function that reads the current date. It currently treats an item as due through the end of its due date. Ask for a test seam and two boundary cases.What to check
The plan identifies a clock or date input that can be controlled and gives separate assertions for the due date and the day after.
Original SKILL.md on GitHub · Updated
Frequently asked question
What should a characterization test assert?
Use the behavior you observed before the refactor. Record any surprising output so a later behavior change can be reviewed separately.