wondelai/skills · plugins/wondelai-skills/skills/working-with-legacy-code/SKILL.md

working-with-legacy-code skillA

working-with-legacy-code is agent-read markdown (skill) from wondelai/skills: Safely change and test untested codebases using Feathers'' "Working Effectively with Legacy Code". Use when the user mentions "legacy code", "no tests", "untested codebase", "how do I test this", "seams", "characterization tests", "golden master", "sprout method", "afraid to change this code", "monster method", "dependency breaking", or "inherited a messy codebase". Also trigger when changing code without tests safely, getting a class under test when constructors, statics, or singletons block it.

Indexed from public GitHub and served as immutable, content-addressed versions. Install it pinned to an exact SHA-256 with the mdr CLI, and every file is verified against the hash recorded here before it reaches your agent. The deterministic audit below grades the latest version, and the same file always earns the same grade.

How to install

Latest version
mdr add wondelai/skills/working-with-legacy-code@v1.2.0
Exact content
mdr add wondelai/skills/working-with-legacy-code@sha256:4a621798f9a51ad1

Pin to a label to follow the author's releases, or to a sha256 to freeze the exact bytes forever. Either way the resolved hash is written to mdr.lock, and mdr install reproduces it on any machine.

Badge

mdr badge

[![mdr](https://markdownregistry.com/badge/art_jdcwcevkmpnb2g4e.svg)](https://markdownregistry.com/a/art_jdcwcevkmpnb2g4e)

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Versions

versioncommittedcommitsizeaudit
v1.2.0 latest2026-08-09 ab2d28a 19,511 BA view

Audit of the latest version

A  17 of 17 checks passed. Deterministic, no model, same answer every run.
  • pass: Frontmatter block present
  • pass: Frontmatter declares a name
  • pass: Frontmatter declares a description
  • pass: Size between 200 bytes and 200 KB (19511 bytes)
  • pass: No zero-width or bidi control characters
  • pass: No instruction hidden inside an HTML comment
  • pass: No link to an exfiltration or paste host
  • pass: No credential-shaped string
  • pass: No instruction to send local credentials anywhere
  • pass: No text hidden with inline styles
  • pass: No prompt-injection phrasing
  • pass: No curl or wget piped into a shell
  • pass: No recursive delete of root, home or parent
  • pass: No instruction to read or print local credentials
  • pass: No base64 blob over 200 characters
  • pass: No link to a raw IP address
  • pass: No script tag

Source

GitHub

wondelai/skills · 2,199 stars · license MIT · pushed 2026-09-10 · branch main

API

GET https://markdownregistry.com/api/v1/artifacts/art_jdcwcevkmpnb2g4e
GET https://markdownregistry.com/api/v1/resolve?ref=wondelai/skills/working-with-legacy-code
GET https://markdownregistry.com/api/v1/blob/4a621798f9a51ad1438f5b25b168615b7caeb540378c8f4d70ab733523135e21

Agents talk at modelranch.com: hand yours the instructions there and it joins the network that reads files like this one.