The description names the domain (legacy system migrations, codebase modernization) and lists several scenarios, but it focuses more on 'when to use' triggers than on concrete actions the skill performs. It never clearly states what the skill actually does (e.g., 'generates migration plans', 'produces refactoring roadmaps').

The 'when' is thoroughly covered with explicit trigger scenarios and even negative boundaries (Do NOT use for...), but the 'what does this do' is essentially missing — the description never states what actions or outputs the skill produces.

Excellent coverage of natural trigger terms: 'legacy system migrations', 'codebase modernization', 'monolith decomposition', 'microservices consolidation', 'cross-language rewrites', 'framework upgrades', 'strangler fig pattern', 'incremental migration strategy', 'refactoring roadmaps'. These are terms users would naturally use.

The description explicitly delineates boundaries by naming three other skills that handle adjacent concerns (domain-analysis, component-identification-sizing, decomposition-planning-roadmap), making it highly distinctive and unlikely to conflict.

The skill is mostly efficient but has some redundancy — the core principles repeat constraints that appear again in the MUST DO/MUST NOT DO section (e.g., 'never assume' and 'always cite evidence' are restated). The ASCII workflow diagram is helpful but the surrounding prose could be tighter. Overall reasonable but not maximally lean.

The skill provides a clear process structure and specific output file paths, but the actual detailed instructions are deferred to reference files (references/research-phase.md, references/plan-phase.md, etc.). The main skill body describes what to do at a high level but lacks concrete examples of what a domain migration file should contain, what the risk matrix looks like, or what specific commands/tools to use. It's more of a framework than executable guidance.

The two-phase workflow (RESEARCH → PLAN) is clearly sequenced with explicit ordering ('Never skip RESEARCH. Never start PLAN without completing RESEARCH.'). Each phase has numbered steps with clear outputs. The constraint that every migration step must include a rollback strategy serves as a validation checkpoint. The workflow is well-structured with clear dependencies between phases.

Excellent progressive disclosure — the skill provides a clear overview with a well-organized reference table that maps topics to specific reference files with explicit 'Load When' conditions. References are one level deep, clearly signaled, and the instruction to 'not preload all references' demonstrates thoughtful context management. The output structure is clearly laid out.