working-effectively-with-legacy-code
Apply Michael Feathers-inspired legacy-code rules when changing hard-to-test code safely with characterization tests, seams, sprout methods, or wrap methods.
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- Repository
- ciembor/agent-rules-books
- Last source activity
- September 9, 2026 at 13:30
- Detected SKILL.md language
- English
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- 3,227
- Forks
- 561
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- working-effectively-with-legacy-code
- description
- Apply Michael Feathers-inspired legacy-code rules when changing hard-to-test code safely with characterization tests, seams, sprout methods, or wrap methods.
- license
- MIT
# Working Effectively with Legacy Code Skill
Use this skill when a task involves risky legacy changes, missing tests, characterization tests, seams, dependency breaking, sprout method, wrap method, or incremental risk reduction.
Before making design or code decisions, read and apply [working-effectively-with-legacy-code.mini.md](working-effectively-with-legacy-code.mini.md). Use [working-effectively-with-legacy-code.md](working-effectively-with-legacy-code.md) only as a deeper reference when the mini rules are not enough for the current legacy-code tradeoff.
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