Code Refactoring Workflow
luongnv89/claude-howto
Guides systematic, test-backed refactoring in the style of Martin Fowler, moving through research, planning and small incremental changes with your approval at each phase.
Refactor legacy codebases, migrate outdated frameworks, and implement gradual modernization.
Install Legacy Modernizer
$ npx skills add aiskillstore/marketplace --skill legacy-modernizer -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install aiskillstore/marketplace legacy-modernizer --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/aiskillstore/marketplace.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/sickn33/legacy-modernizer .claude/skills/legacy-modernizer && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "legacy-modernizer" agent skill from https://github.com/aiskillstore/marketplace/tree/main/skills/sickn33/legacy-modernizer into .claude/skills/legacy-modernizer/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "legacy-modernizer", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/aiskillstore/marketplace/tree/main/skills/sickn33/legacy-modernizerType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add aiskillstore/marketplace --skill legacy-modernizer -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install aiskillstore/marketplace legacy-modernizer --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/aiskillstore/marketplace.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/sickn33/legacy-modernizer .agents/skills/legacy-modernizer && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "legacy-modernizer" agent skill from https://github.com/aiskillstore/marketplace/tree/main/skills/sickn33/legacy-modernizer into .agents/skills/legacy-modernizer/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "legacy-modernizer", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add aiskillstore/marketplace --skill legacy-modernizer -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install aiskillstore/marketplace legacy-modernizer --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/aiskillstore/marketplace.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/sickn33/legacy-modernizer .cursor/skills/legacy-modernizer && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "legacy-modernizer" agent skill from https://github.com/aiskillstore/marketplace/tree/main/skills/sickn33/legacy-modernizer into .cursor/skills/legacy-modernizer/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "legacy-modernizer", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/aiskillstore/marketplace.git --path skills/sickn33/legacy-modernizer--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add aiskillstore/marketplace --skill legacy-modernizer -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install aiskillstore/marketplace legacy-modernizer --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/aiskillstore/marketplace.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/sickn33/legacy-modernizer .gemini/skills/legacy-modernizer && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "legacy-modernizer" agent skill from https://github.com/aiskillstore/marketplace/tree/main/skills/sickn33/legacy-modernizer into .gemini/skills/legacy-modernizer/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "legacy-modernizer", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install aiskillstore/marketplace legacy-modernizerInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add aiskillstore/marketplace --skill legacy-modernizer -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/aiskillstore/marketplace.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/sickn33/legacy-modernizer .github/skills/legacy-modernizer && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "legacy-modernizer" agent skill from https://github.com/aiskillstore/marketplace/tree/main/skills/sickn33/legacy-modernizer into .github/skills/legacy-modernizer/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "legacy-modernizer", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add aiskillstore/marketplace --skill legacy-modernizer -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install aiskillstore/marketplace legacy-modernizer --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/aiskillstore/marketplace.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/sickn33/legacy-modernizer .opencode/skills/legacy-modernizer && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "legacy-modernizer" agent skill from https://github.com/aiskillstore/marketplace/tree/main/skills/sickn33/legacy-modernizer into .opencode/skills/legacy-modernizer/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "legacy-modernizer", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
legacy-modernizer- GitHub stars
- 433
- Used in
- 6 other repos
- Token cost
- ~441 tokens
- SKILL.md length
- 179 words
- Files
- 2
- Skills in repo
- 1,044
- Repo updated
- First seen
- Licence
- None found
At a glance
Refactor legacy codebases, migrate outdated frameworks, and implement gradual modernization.
- Works in 5 steps: Strangler fig pattern - gradual… → Add tests before refactoring → Maintain backward compatibility → …
- Tasks that involve Legacy modernization
- SKILL.md covers Use this skill when, Do not use this skill when, Instructions and Focus Areas, plus 2 more sections
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
What it does
Legacy Modernizer is an agent skill from aiskillstore/marketplace. Refactor legacy codebases, migrate outdated frameworks, and implement gradual modernization. Handles technical debt, dependency updates, and backward compatibility. Use PROACTIVELY for legacy system updates, framework migrations, or technical debt reduction.
Its SKILL.md is about 440 tokens, which your agent loads only when the skill is triggered. The skill folder holds 1 other file (for example `skill-report.json`).
It sits in Development, covering Legacy modernization. The repository describes itself as: Security-audited skills for Claude, Codex & Claude Code. One-click install, quality verified.
When your agent uses it
- Tasks that involve Legacy modernization
Example prompts
- “/legacy-modernizer”
Requirements
- Python 3
Workflow steps
5 steps, taken from the first numbered list in SKILL.md.
- Strangler fig pattern - gradual replacement
- Add tests before refactoring
- Maintain backward compatibility
- Document breaking changes clearly
- Feature flags for gradual rollout
What it can do on your machine
Read from SKILL.md and the folder at commit 44923f3. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md.
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Legacy Modernizer loads about 441 tokens when it runs. Until then it costs about 69 tokens; SKILL.md has 179 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
Without a licence we can't republish the file, so here is its outline and opening line. It has 179 words (~441 tokens).
“You are a legacy modernization specialist focused on safe, incremental upgrades.”
- name
- legacy-modernizer
- metadata.model
- sonnet
Files
SKILL.md and 1 other file in skills/sickn33/legacy-modernizer of aiskillstore/marketplace.
- SKILL.md
- skill-report.json
Open the folder on GitHubat commit 44923f3
Used in 6 other repositories
We found 15 copies of this SKILL.md (exact, near-identical or edited) in other folders, from 6 other GitHub owners. This page covers the copy in aiskillstore/marketplace, which our catalogue first saw on October 7, 2026.
- sickn33/agentic-awesome-skillsskills/legacy-modernizerplugins/agentic-awesome-skills/skills/legacy-modernizer+1 more
- rmyndharis/antigravity-skillsskills/legacy-modernizer
- agent-skills-hub/agent-skills-hubskills/legacy-modernizer
- lingxling/awesome-skills-cnantigravity-awesome-skills/skills/legacy-modernizerantigravity-awesome-skills/plugins/agentic-awesome-skills/skills/legacy-modernizer+1 more
- benjaminasterA/antigravity-awesome-skillsskills/legacy-modernizer
- henryalouf/ruflow.agents/skills/legacy-modernizer.agents/skills/antigravity-awesome-skills/skills/legacy-modernizer+4 more
Compare with similar skills
Legacy Modernizer next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Legacy Modernizer this skillaiskillstore/marketplace | 433 | 6 repos | ~441 | Automated safety check: Pass | None | |
| Code Refactoring Workflowluongnv89/claude-howto | 42k | — | ~3.1k | Automated safety check: Pass | MIT | |
| Convert Internal Package to TypeScriptTryGhost/Ghost | 56k | — | ~1.2k | Automated safety check: Pass | MIT | |
| jscpd Code Migration Trackerkucherenko/jscpd | 6.4k | — | ~5k | Automated safety check: Pass | MIT | |
| Rails Upgrade Assistantombulabs/claude-code_rails-upgrade-skill | 391 | — | ~2.7k | Automated safety check: Pass | MIT | |
| Migrate Dotnet8 To Dotnet9dotnet/skills | 5.6k | 2 repos | ~3.9k | Automated safety check: Pass | MIT |
Similar skills
Convert Internal Package to TypeScript
TryGhost/Ghost
Moves a legacy internal Ghost package from JavaScript and CommonJS to TypeScript and ESM in three focused commits that keep git file history intact.
jscpd Code Migration Tracker
kucherenko/jscpd
Measures a code port between languages or frameworks with jscpd's function-level comparison, porting tests before code and tracking what is left unmatched.
Rails Upgrade Assistant
ombulabs/claude-code_rails-upgrade-skill
Analyzes a Rails app and builds an upgrade report with breaking changes, deprecations and step-by-step migration guides, one version at a time from Rails 2.3 through 8.1.
- Official
Migrate Dotnet8 To Dotnet9
dotnet/skills
Migrate a .NET 8 project to .NET 9 and resolve all breaking changes.
Msbuild Antipatterns
runceel/ReactiveProperty
Catalog of MSBuild anti-patterns with detection rules and fix recipes.
More from aiskillstore/marketplace
All 1,044 skills in this repoCode Stats
aiskillstore/marketplace
Analyze codebase with tokei (fast line counts by language) and difft (semantic AST-aware diffs).
Data Processing
aiskillstore/marketplace
Process JSON with jq and YAML/TOML with yq. An agent skill from aiskillstore/marketplace.
Doc Scanner
aiskillstore/marketplace
Scans for project documentation files (AGENTS.md, CLAUDE.md, GEMINI.md, COPILOT.md, CURSOR.md, WARP.md, and 15+ other formats) and synthesizes guidance.
File Search
aiskillstore/marketplace
Modern file and content search using fd, ripgrep (rg), and fzf.
Find Replace
aiskillstore/marketplace
Modern find-and-replace using sd (simpler than sed) and batch replacement patterns.
Project Planner
aiskillstore/marketplace
Detects stale project plans and suggests session commands. An agent skill from aiskillstore/marketplace.
Related
Categories
Questions about Legacy Modernizer
What does Legacy Modernizer do?
Refactor legacy codebases, migrate outdated frameworks, and implement gradual modernization. Legacy Modernizer is an agent skill from aiskillstore/marketplace. Refactor legacy codebases, migrate outdated frameworks, and implement gradual modernization.
When should I use Legacy Modernizer?
Legacy Modernizer fits situations like: tasks that involve Legacy modernization.
How do I install Legacy Modernizer in Claude Code?
Run `npx skills add aiskillstore/marketplace --skill legacy-modernizer -a claude-code`. Or copy the skill folder (skills/sickn33/legacy-modernizer in aiskillstore/marketplace) into .claude/skills/legacy-modernizer in your project. Claude Code loads it when a task matches its description.
How do I install Legacy Modernizer in Codex?
Run `npx skills add aiskillstore/marketplace --skill legacy-modernizer -a codex`. Or copy the skill folder (skills/sickn33/legacy-modernizer in aiskillstore/marketplace) into .agents/skills/legacy-modernizer in your project. Codex loads it when a task matches its description.
Can I use Legacy Modernizer in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add aiskillstore/marketplace --skill legacy-modernizer -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/legacy-modernizer, .gemini/skills/legacy-modernizer, .github/skills/legacy-modernizer and .opencode/skills/legacy-modernizer in your project.
What does Legacy Modernizer need to run?
SKILL.md names no scripts, command-line tools or credentials: Legacy Modernizer is instructions for the agent only. Our summary lists: Python 3.
Does Legacy Modernizer access the network?
SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.
Is Legacy Modernizer safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does Legacy Modernizer use?
No licence was found for Legacy Modernizer or its repository. Without one, default copyright applies: ask the author before reusing or redistributing it.
How many tokens does Legacy Modernizer use?
About 441 tokens (SKILL.md is roughly 1.8k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.
What are the alternatives to Legacy Modernizer?
Skills that share tags, products or a category with Legacy Modernizer: Code Refactoring Workflow (luongnv89/claude-howto, 42k stars), Convert Internal Package to TypeScript (TryGhost/Ghost, 56k stars), jscpd Code Migration Tracker (kucherenko/jscpd, 6.4k stars) and Rails Upgrade Assistant (ombulabs/claude-code_rails-upgrade-skill, 391 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Legacy Modernizer?
aiskillstore (a GitHub organization) maintains it in aiskillstore/marketplace, which has 433 GitHub stars. The repository holds 1,044 skills in this directory. The repository was last updated on October 10, 2026.
Source: aiskillstore/marketplace on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.