working-effectively-with-legacy-code
About working-effectively-with-legacy-code
A development skill for reducing risk when changing legacy code, especially where tests are missing. It prioritizes concise guidance and refers to a fuller document for difficult tradeoffs.
Key features
- 01Guidance for risky legacy changes
- 02Characterization testing
- 03Seams and dependency breaking
- 04Sprout and wrap methods
- 05Incremental risk reduction
- 06Short rules with a deeper reference
Use cases
- 01Changing legacy code without tests
- 02Adding characterization tests
- 03Breaking dependencies incrementally
Install
Copy the command and run it in a terminal.
npx skills add https:/After installing, type/working-effectively-with-legacy-codein Claude Code to confirm it loaded.
Bundled files
References and scripts installed along with SKILL.md.
working-effectively-with-legacy-code.mdworking-effectively-with-legacy-code.mini.mdworking-effectively-with-legacy-code.nano.mdDetails
From the project READMEWorking 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. Use working-effectively-with-legacy-code.md only as a deeper reference when the mini rules are not enough for the current legacy-code tradeoff.