legacy-modernizer

An agent skill by Jeffallan, from Jeffallan/claude-skills. Tags: api, automation, developer-tools, documentation, migration, strategy.

What it does

Designs incremental migration strategies, identifies service boundaries, produces dependency maps and migration roadmaps, and generates API facade designs for aging codebases. Use when modernizing legacy systems, implementing strangler fig pattern or branch by abstraction, decomposing monoliths, upgrading frameworks or languages, or reducing technical debt without disrupting business operations.

Install

With the skills CLI, which installs into Claude Code, Codex, Cursor and other agents:

npx skills add Jeffallan/claude-skills --skill legacy-modernizer

Or copy the skill folder into Claude Code's skills directory by hand (~/.claude/skills for every project, or .claude/skills inside one):

git clone --depth 1 https://github.com/Jeffallan/claude-skills
cp -r claude-skills/skills/legacy-modernizer ~/.claude/skills/legacy-modernizer

Safety box score

Not rated yet. A safety box score grades what a skill and its scripts can reach on the machine of whoever installs it, across eight categories from shell execution to secrets access. Anyone can request one from this page; it is saved for everyone. How the score works.

Source

Repository

Jeffallan/claude-skills (all skills from this repository)

Path

skills/legacy-modernizer/SKILL.md

Branch

main

Updated

2026-09-19

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