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dfedoryshchevdfedoryshchev/weftworks/skills/safe-refactor/SKILL.md

safe-refactor

Skill5 starsChanged 2 months agoMITView on GitHub

change legacy code you don't fully trust without breaking it - characterize first

26 other projects use a version of this.

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Used with

Projects with it also use verify-and-stop, investigate-first and 10 more.

Other files people use alongside this one.

Files found in the same public projects as a version of this one, more often than they turn up anywhere else. Each project counts once, large collections count for less, and this file's own repository is left out.
  • JuliusBrusseeSkill

    verify-and-stop

    Prove existing work meets acceptance conditions without expanding scope. Use for validation-only tasks, completion checks, focused gate runs, and last-mile proof.

    Also in 8 projects that use this

  • JuliusBrusseeSkill

    investigate-first

    Diagnose ambiguous failures before editing. Use for unknown causes, intermittent behavior, performance regressions, or investigations needing evidence-ranked hypotheses.

    Also in 7 projects that use this

  • +10 more from JuliusBrussee

The file

We split this skill into the rules it gives an agent

1 rule. 0 are common, 1 is distinctive, and 0 are very specific to this project.

  • 0

    Common

    Most of the 24 edited versions we read keep these.

  • 1

    Distinctive

    This author's own choices. Worth a look.

  • 0

    Very specific

    Tied to their project's names, files or tools. Probably skip.

  • Common
  • Distinctive
  • Very specific
  1. Distinctive:

    characterize: write tests that capture what it does NOW, bugs and all.

    line 10

“Common” is measured: kept by at least 6 in 10 of the 24 edited versions of this file we could read. “Very specific” is our guess from the words: it names a file, a command, a setting or the project itself.

Keep what fits and drop the rest. Your version, ready for your agents.
Files
SKILL.md

safe-refactor

for code that has no tests and no one remembers:

  1. characterize. write tests that capture what it does NOW, bugs and all. you're not fixing yet, you're pinning behaviour.
  2. map the blast radius (dependency-check skill) - who calls this, what breaks if it moves.
  3. change in small reversible steps, running the characterization tests each time.
  4. only then fix the behaviour you actually meant to, with a red test first.

the order matters: make it safe to change before you change it. most "risky refactors" are just refactors done without step 1.

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