Legacy System Archaeologist
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
Sample input
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.
Sample output
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
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
Sample input
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.
Sample output
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.
Screenshots
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.
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Security Scanned
Passed automated security review
Permissions
Claude Code, Cursor, Windsurf, GitHub Copilot CLI