Legacy System Archaeologist
by J. Trejo
Reconstruct architecture and map risks in inherited legacy codebases with evidence-based auditing and migration plans.
- Audit inherited codebases to identify high-risk "god objects" and coupling.
- Generate a Strangler Fig migration plan for monolith decomposition.
- Identify likely dead code candidates based on static analysis and git churn.
Free
Included in download
- Downloadable skill package
- Works with Claude Code, Cursor
- 2 permissions declared
Media gallery
See it in action
You say
I've inherited this messy monolith and need to know what's safe to touch. Analyze the codebase, check the billing logic, and give me a risk assessment and migration plan.
Your agent does
System Health: CRITICAL Risk Register:
- /app/services/billing_engine.rb: BLACK (High fan-in: 42, Git churn: high, 0 tests)
- /lib/legacy_utils.js: RED (Dead code candidate, but dynamic dispatch possible) Plan: Implement 5 characterization tests on billing_engine before refactoring.
Legacy System Archaeologist
by J. Trejo
Reconstruct architecture and map risks in inherited legacy codebases with evidence-based auditing and migration plans.
Free
Included in download
- Downloadable skill package
- Works with Claude Code, Cursor
- 2 permissions declared
- Instant install
Media gallery
See it in action
You say
I've inherited this messy monolith and need to know what's safe to touch. Analyze the codebase, check the billing logic, and give me a risk assessment and migration plan.
Your agent does
System Health: CRITICAL Risk Register:
- /app/services/billing_engine.rb: BLACK (High fan-in: 42, Git churn: high, 0 tests)
- /lib/legacy_utils.js: RED (Dead code candidate, but dynamic dispatch possible) Plan: Implement 5 characterization tests on billing_engine before refactoring.
About This Skill
What it does
The Legacy System Archaeologist is a specialized toolkit for developers who have inherited "black box" codebases. It performs deep structural analysis to reconstruct system architecture, map dependencies, and identify high-risk modules before you write a single line of code.
Why use this skill
Modernizing legacy systems is dangerous because the "why" and "how" are often lost to time. While a standard AI might give you generic refactoring advice, this skill uses a rigorous 6-phase protocol—Inventory, Dependency Mapping, Risk Scoring, Dead Code Analysis, Architecture Reconstruction, and Strategy Reporting—to provide evidence-based insights.
It goes beyond simple prompting by using dedicated scripts to calculate "fan-in" (coupling), git churn (instability), and risk classifications. You get a professional-grade audit that identifies "Black Zone" files (like auth or payments) that no agent or human should touch without characterization tests.
Supported tools
- Languages: Multi-framework support (Rails, Laravel, Django, Node, Spring, .NET)
- Analysis Scripts: Python-based dependency graphers and risk scorers
- Context: Git history analysis and static code analysis
The Result
You receive a structured documentation suite including an Executive Summary for stakeholders, a full System Map, a file-level Risk Register, and a phased Migration Plan based on the Strangler Fig pattern.
Use Cases
- Audit inherited codebases to identify high-risk "god objects" and coupling.
- Generate a Strangler Fig migration plan for monolith decomposition.
- Identify likely dead code candidates based on static analysis and git churn.
- Create a System Map for onboarding new engineers to undocumented projects.
- Flag "AI Danger Zones" where agents should not perform automated refactoring.
Known Limitations
Scope: static only, no runtime, no logs, no DB, results hint not truth, human check needed Language: full Python JS TS Ruby, weak Kotlin Rust Scala C#, frameworks mostly Rails Django Node, can misread Dependencies: Python top-level only, JS/TS weak on dynamic/aliases, cycles shallow Dead code: text match only, not real proof, misses dynamic, queues, webhooks, cron Risk: keyword based, false hits, false misses, not security audit Repo: needs full repo, Git stats need full .git, ZIP no churn Performance: big repo slow, full scans heavy Non-goals: not code review, not testing, not security, not compliance
How to Install
mkdir -p ~/.claude/skills && curl -sL https://www.agensi.io/api/install/legacy-system-archaeologist -o /tmp/legacy-system-archaeologist.zip && unzip -o /tmp/legacy-system-archaeologist.zip -d ~/.claude/skills && rm /tmp/legacy-system-archaeologist.zipFree skills install directly. Paid skills require purchase - use the download button above after buying.
Reviews
No reviews yet - be the first to share your experience.
Only users who have downloaded or purchased this skill can leave a review.
No reviews yet - be the first to share your experience.
Only users who have downloaded or purchased this skill can leave a review.
Security Scanned
Passed automated security review
Permissions
Claude Code, Cursor, Windsurf, GitHub Copilot CLI
Creator
Frequently Asked Questions
Learn More About AI Agent Skills
More Premium Skills
Legacy Code Modernization Planner for AI Coding Agents
Creates safe modernization roadmaps for old, messy, undocumented, or fragile codebases, including risk audits, refactor phases, dependency reviews, testing plans, migration steps, and AI coding prompts.
designing-hybrid-context-layers
Architects the right retrieval strategy for every query — teaching your agent when to use RAG, a knowledge graph, or a temporal index instead of defaulting to vector search for everything.
World-Class Site & App Design
Every AI-built UI looks generic and templated. This skill teaches your agent to actually match the design to the project, the industry, and the audience.
ai-automation-qa-pack
Professional QA & UAT documentation generator for AI automation agencies and complex agent deployments.