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legacy

Modernize legacy codebases with characterization tests, dead-code removal, and dependency upgrades.

26|8|Updated Mar 19, 2026
Search Tags:#security#refactoring#modernization#legacy#dead-code#characterization-tests#dependency-upgrades
One-click install
npx skills add https://github.com/arbazkhan971/godmode --skill legacy-arbazkhan971
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: legacy
Source: https://github.com/arbazkhan971/godmode/tree/main/skills/legacy
Command: npx skills add https://github.com/arbazkhan971/godmode --skill legacy-arbazkhan971

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Legacy addresses the risk, cost, and inertia of aging codebases by providing a structured, safety-first workflow to understand, test, and modernize legacy code without introducing regressions.

Core Features & Use Cases

  • Characterization first: generate characterization and golden-master tests to capture existing behavior before any change.
  • Safe incremental modernization: enforce small, reversible PRs, prioritized dependency upgrades, and guarded refactors to reduce tech debt.
  • Dead code and dependency management: detect likely dead code with multiple signals and plan upgrades for EOL or vulnerable dependencies.
  • Use case: take a monolithic repo with no tests and iteratively add tests, remove dead code, and upgrade critical dependencies while preserving behavior.

Quick Start

Ask the skill to run a legacy assessment, create characterization tests for critical paths, and propose a prioritized modernization plan.

Frequently Asked Questions about legacy

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I safely refactor a legacy codebase with no existing tests?▼

To safely refactor legacy code without tests, generate characterization and golden-master tests first to capture existing behavior. This ensures you preserve current functionality by validating outputs before making any structural changes or refactors.

What is the best way to identify and remove dead code in an aging repository?▼

To identify and remove dead code safely, use a two-signal confirmation approach. This requires multiple detection signals to verify code is truly unused before deletion, preventing accidental removal of active paths during legacy modernization.

How do I upgrade EOL or vulnerable dependencies in a monolithic repo?▼

To upgrade vulnerable dependencies in a monolithic repo, plan prioritized, incremental upgrades. Run security and dependency checks between major upgrades, enforcing small, reversible changes per PR to prevent regressions and minimize modernization risks.

Can I modernize a large monolithic file incrementally without breaking existing behavior?▼

Yes, you can modernize large monolithic files incrementally by enforcing small, reversible changes per pull request. This structured approach relies on tests-before-refactor rules to ensure existing behavior remains unbroken throughout the modernization workflow.

When should I not attempt a direct code refactor during modernization?▼

You should not attempt a direct code refactor before establishing characterization tests. Skipping behavior-capturing tests risks introducing regressions, as there is no baseline to verify that existing functionality remains intact after structural changes.

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