# code modernization — Agent Skill

Guided modernization for any legacy codebase: start with /modernize, get an assessment, an interactive map, the business rules mined from the code, and a plan you approve, then an upgrade, a rewrite or a rebuild with independent proof that the new code behaves like the old. Includes security hardening, a one-page repo…

## At a glance

code-modernization is an Agent Skill by anthropics in the Coding & Engineering category. In Claude Code it installs with `/plugin install code-modernization@claude-plugins-official` after adding the anthropics/claude-plugins-official marketplace; other assistants use its SKILL.md instructions as rules. Its source repository has 45,210 GitHub stars (as of Oct 28, 2026).

## Install

### How to install code modernization in Claude Code

1. Add the marketplace

```claude
/plugin marketplace add anthropics/claude-plugins-official
```

2. Install the skill

```claude
/plugin install code-modernization@claude-plugins-official
```

3. Use it

   These are slash commands for a Claude Code session, not your shell. Claude auto-invokes the skill when your request matches its description — or type its slash command if it exposes one.

### How to install code modernization in Claude Desktop

1. Clone the source

```bash
git clone https://github.com/anthropics/claude-plugins-official.git
```

2. Find the skill

   It lives in claude-plugins-official/plugins/code-modernization — that folder contains the SKILL.md.

3. Add the SKILL.md to your Skills folder

   Settings → Capabilities → Skills → add the folder containing SKILL.md. Claude picks it up automatically.

### How to install code modernization in Cursor

1. Clone the source

```bash
git clone https://github.com/anthropics/claude-plugins-official.git
```

2. Find the skill

   It lives in claude-plugins-official/plugins/code-modernization — that folder contains the SKILL.md.

3. Convert to a Cursor rule

   Create .cursor/rules/code-modernization.mdc and paste the SKILL.md body. Set `alwaysApply` or a glob so the Agent loads it in context.

### How to install code modernization in Codex CLI

1. Clone the source

```bash
git clone https://github.com/anthropics/claude-plugins-official.git
```

2. Find the skill

   It lives in claude-plugins-official/plugins/code-modernization — that folder contains the SKILL.md.

3. Reference in AGENTS.md

   Add the skill's instructions (or a link) to AGENTS.md at your repo root — Codex reads it on every run.

### How to install code modernization in Windsurf

1. Clone the source

```bash
git clone https://github.com/anthropics/claude-plugins-official.git
```

2. Find the skill

   It lives in claude-plugins-official/plugins/code-modernization — that folder contains the SKILL.md.

3. Add to your rules / context

   Paste the SKILL.md instructions into this tool's custom rules or workspace instructions so the agent follows them.

### How to install code modernization in Cline

1. Clone the source

```bash
git clone https://github.com/anthropics/claude-plugins-official.git
```

2. Find the skill

   It lives in claude-plugins-official/plugins/code-modernization — that folder contains the SKILL.md.

3. Add to your rules / context

   Paste the SKILL.md instructions into this tool's custom rules or workspace instructions so the agent follows them.

### How to install code modernization in VS Code

1. Clone the source

```bash
git clone https://github.com/anthropics/claude-plugins-official.git
```

2. Find the skill

   It lives in claude-plugins-official/plugins/code-modernization — that folder contains the SKILL.md.

3. Add to your rules / context

   Paste the SKILL.md instructions into this tool's custom rules or workspace instructions so the agent follows them.

Source: https://github.com/anthropics/claude-plugins-official/tree/main/plugins/code-modernization

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Source: https://mcp-skills-hub.vercel.app/skills/code-modernization · MCP Skills Hub · data as of 2026-10-28T12:31:05Z