Code Modernization (plugin officiel Anthropic)
Official Anthropic plugin to modernise an old codebase (legacy COBOL, Java, C++ or .NET, web monoliths) without asking Claude to rewrite everything at once. It enforces an order: `/modernize-preflight` checks the environment and detects the stack, `/modernize-assess` inventories languages, complexity, debt and security, `/modernize-map` draws the dependency map as an interactive page, `/modernize-extract-rules` mines business rules into Given/When/Then cards that cite the code, and `/modernize-brief` turns all that into a phased plan acting as an approval gate. These analyses land in `analysis/<system>/`. Only then come three build paths in `modernized/<system>/`: `transform` (rewrite to another stack), `reimagine` (rebuild on a new architecture) or `uplift` (version bump on the same stack, for example .NET Framework to .NET 8). `/modernize-harden` runs a security pass on the legacy system without editing it.
Strengths
- An enforced order (understand, map, extract rules, approve) before a single line is rewritten
- Characterisation tests proving the modernised version behaves like the old one
- Deliverables a steering committee can read: assessment, interactive map, cited business rules, phased plan
Limitations
- Extracted business rules are inferences: they need review by someone who knows the domain
- A long, token-hungry path on a large system, oversized for a small recent codebase
Best for
- Preparing the migration of an old undocumented application, starting by understanding what it does
- Bumping a framework version (.NET Framework to .NET 8) with proof that nothing drifted
- Producing the assessment and phased plan a committee must approve before funding a rebuild