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🏛️ Legacy Modernizer Master Kit · dokhacgiakhoa | DecimalAI

codingby dokhacgiakhoa

🏛️ Legacy Modernizer Master Kit

dokhacgiakhoa/legacy-modernizer

Source dokhacgiakhoa/agent-skills-4-vibe-coding-cli ↗License NOASSERTION

Refactor legacy codebases, migrate outdated frameworks, and implement gradual modernization.

SkillScore82Maintained

Automatic

Coding pack

Last verified 8/29/2026

What it changes

Passed 18 of 22 test cases with the skill, and 16 of 22 without it.

Without skill73%

With skill82%

Checks it passed that the model alone missed

Recommends completely deleting the legacy source code
Specifies `npm update express` to perform the patch version upgrade
Recommends conducting a technical debt audit to establish a migration roadmap

3 fixed15 passed either way3 still failing1 broke

Pass-rate lift: +9 pp
Tokens: +20%
Agent turns: 0%
Response time: +2%

Model gemini-3.6-flashMeasured 8/29/2026v118 of 22 cases passed with skill

Tokens, turns and time describe resource use, not a dollar price.

Use this skill

Save it into your project's skills folder. Claude Code picks it up in its next session.

curl -fsSL --create-dirs -o .claude/skills/dokhacgiakhoa-legacy-modernizer/SKILL.md https://app.decimal.ai/s/dokhacgiakhoa-legacy-modernizer/SKILL.md

Want it pinned and updatable? pip install "decimalai>=0.15", then decimalai skills add dokhacgiakhoa-legacy-modernizer, and start Claude Code with claude --plugin-dir "$(git rev-parse --show-toplevel)/.agents"

1 · One-time — install the CLI (docs ↗)

pip install "decimalai>=0.15"

2 · Get the skill — writes .agents/skills/dokhacgiakhoa-legacy-modernizer/ and pins it in .decimal/skills.lock

decimalai skills add dokhacgiakhoa-legacy-modernizer

No CLI? Get the same file — curl · raw file

curl -fsSL --create-dirs -o .claude/skills/dokhacgiakhoa-legacy-modernizer/SKILL.md https://app.decimal.ai/s/dokhacgiakhoa-legacy-modernizer/SKILL.md

Raw file: /s/dokhacgiakhoa-legacy-modernizer/SKILL.md ↗ · machine-readable summary at /s/dokhacgiakhoa-legacy-modernizer.json ↗

Safety checks: 3 of 3 passed

Code scan CleanIntent PassedContent Clean

See it in action

One of 3 test cases the skill fixed. Same model, same prompt, with and without the skill.

1 of 3

Prompt

We maintain a Node.js web application running on Node 20 with `express` version 4.18.1. We want to update `express` to the latest patch version 4.18.2 to apply security fixes without performing major version upgrades. What npm CLI command applies this patch update?

What was checked, without and with the skill
Checked	Without skill	With skill
Specifies `npm update express` to perform the patch version upgrade	Missed	Passed

case-21 · gemini-3.6-flash · 8/29/2026 · answers are capped and redacted

What's inside

The instructions your model reads when the skill loads.

SKILL.md65 lines3 filesincludes scripts

🏛️ Legacy Modernizer Master Kit

You are a Principal Modernization Engineer and Software Strategist. You transform "Ball of Mud" architectures into clean, modern, and performant systems without braking existing business value.

📑 Internal Menu

Modernization Strategy (Strangler Fig)
Dependency & Version Upgrades
Code Migration & Refactoring
Framework Transitions (e.g., Angular to React)
Validation & Backward Compatibility

1. Modernization Strategy (Strangler Fig)

Identify Borders: Find clear service or module boundaries to extract.
Proxy Layer: Use an API gateway or proxy to route traffic between the old and new systems.
Incremental Extraction: Move one feature at a time, sunsetting the legacy part only when the new one is 100% stable.

2. Dependency & Version Upgrades

Asset Audit: Inventory all outdated 3rd-party libraries.
Breaking Changes: Review changelogs for major version jumps.
Step-by-Step Upgrade: Move through intermediate versions (e.g., v1 -> v2 -> v3) instead of one giant leap.

3. Code Migration & Refactoring

Automated Refactoring: Use tools like putout or jscodeshift for mass renames or syntax updates.
Pattern Transformation: Convert Class components to Hooks, or jQuery to Vanilla JS.
Type Integration: Incrementally add TypeScript to JS projects to ensure type safety during the build.

4. Framework Transitions

Angular-to-React/Vue: Map component logic and state management.
Monolith-to-Microservices: Extract domain logic into independent services.
SSR-to-Streaming: Modernize data-fetching patterns for better performance.

Track record

Benchmark

18 / 22

test cases passed, vs 16 / 22 without

Adoption

Users: 0
Times used: 0

Safety and source details

SkillSafety

✓ 3 of 3 passed

Code scan15 of 15 checks clean

0 critical · 0 warning · 0 info — scanner v4 — 8/10/2026

View 15 scanner checks

live_secretremote_code_executionreverse_shelldata_exfiltrationssrf_metadataagent_snoopinganti_refusaldestructive_commandsobfuscated_unicodeunicode_homoglyphopaque_blobsuspicious_urltool_overreachtrigger_abuseprompt_injection_phrasing

IntentSafe

LLM judge · does the skill do what it claims

ContentClean

LLM judge · policy & harmful-content review

Source

Imported

dokhacgiakhoa / agent-skills-4-vibe-coding-cli

.agent/skills/legacy-modernizer/SKILL.md

View on GitHub ↗

License NOASSERTIONImported 8/10/2026Version v1Bundled 2 files · scripts

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Ready to supercharge your AI agents?

See it in action

What's inside

🏛️ Legacy Modernizer Master Kit

📑 Internal Menu

1. Modernization Strategy (Strangler Fig)

2. Dependency & Version Upgrades

3. Code Migration & Refactoring

4. Framework Transitions

Track record

Benchmark

Adoption

SkillSafety

Source

Other skills for the same job

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