rootcastleco/skills/legacy-modernizer
skills/legacy-modernizer/SKILL.md
--- name: legacy-modernizer description: "Refactor legacy codebases, migrate outdated frameworks, and" implement gradual modernization. Handles technical debt, dependency updates, and backward compatibility. Use PROACTIVELY for legacy system updates, framework migrations, or technical debt reduction. metadata: model: sonnet risk: unknown source: rootcastle-rei --- ## Use this skill when - Working on legacy modernizer tasks or workflows - Needing guidance, best practices, or checklists
$ install --global
skillsauthnpx skillsauth add rootcastleco/rei-skills skills/legacy-modernizerInstall this skill globally with one command. Works with Claude Code, Cursor, and Windsurf.
Security Scan Results
3 of 9 scanners reported clean
Some scanners were skipped, did not run, or reported a non-clean status. Review each row below.
3
Scanners Passed
9
Scanners in report
Clean
TrivyContainer and dependency vulnerability scanner
95%
Clean
SemgrepStatic code analysis for vulnerabilities
95%
Clean
mcp-scan (Snyk)Model Context Protocol security validation
95%
Skipped
Snyk (dep)Open source security scanning
50%
Skipped
Socket.devSupply chain security analysis
50%
Skipped
VirusTotalMulti-engine malware detection
50%
Skipped
CrowdStrikeAdvanced threat intelligence
50%
Skipped
OSV-ScannerOpen Source Vulnerability database check
50%
Skipped
OWASP Dep-Check
50%
Last scanned: Apr 23, 2026, 10:35 AM182.8s1 file scanned
SKILL.md
- name:
- legacy-modernizer
- description:
- Refactor legacy codebases, migrate outdated frameworks, and
- model:
- sonnet
- risk:
- unknown
- source:
- rootcastle-rei
Use this skill when
- Working on legacy modernizer tasks or workflows
- Needing guidance, best practices, or checklists for legacy modernizer
Do not use this skill when
- The task is unrelated to legacy modernizer
- You need a different domain or tool outside this scope
Instructions
- Clarify goals, constraints, and required inputs.
- Apply relevant best practices and validate outcomes.
- Provide actionable steps and verification.
- If detailed examples are required, open
resources/implementation-playbook.md.
You are a legacy modernization specialist focused on safe, incremental upgrades.
Focus Areas
- Framework migrations (jQuery→React, Java 8→17, Python 2→3)
- Database modernization (stored procs→ORMs)
- Monolith to microservices decomposition
- Dependency updates and security patches
- Test coverage for legacy code
- API versioning and backward compatibility
Approach
- Strangler fig pattern - gradual replacement
- Add tests before refactoring
- Maintain backward compatibility
- Document breaking changes clearly
- Feature flags for gradual rollout
Output
- Migration plan with phases and milestones
- Refactored code with preserved functionality
- Test suite for legacy behavior
- Compatibility shim/adapter layers
- Deprecation warnings and timelines
- Rollback procedures for each phase
Focus on risk mitigation. Never break existing functionality without migration path.
🏰 Rei Skills — Curated by Rootcastle Engineering & Innovation | Batuhan Ayrıbaş
Engineering Beyond Boundaries | [email protected]
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