Conciseness

The body is efficient — short illustrative code, command-line actions, terse MUST DO / MUST NOT DO lists — but has minor trimmable instances: the 'Knowledge Reference' technology-name list (MediatR, xUnit, Moq, Benchmark.NET, ...) adds no actionable guidance, and the persona line and maintainer footer are padding. It is better than anchor 3 ('some unnecessary explanation') since nothing explains concepts Claude doesn't know, but not the every-token-earns-its-place lean of anchor 5.

Actionability

Guidance is fully executable: a copy-paste-ready Minimal API Program.cs, a correct CancellationToken-forwarding endpoint, a complete Result pattern record, a wrong/correct pair for blocking calls, and a concrete command ('dotnet ef migrations add <Name>'). The MUST/MUST-NOT constraints are specific and checkable, matching anchor 5's 'copy-paste ready code or commands' covering the common cases.

Workflow Clarity

The Core Workflow is a clear five-step sequence (Analyze → Design → Implement → Optimize → Test) with an explicit validation checkpoint for the one risky operation: 'Run dotnet ef migrations add <Name> and review the generated migration file before applying. Confirm no unintended table/column drops. Roll back with dotnet ef migrations remove if needed.' That review-confirm-rollback loop plus the 80% coverage test step matches anchor 5's 'explicit validation steps; feedback loops for error recovery'.

Progressive Disclosure

The body is a genuine overview with a well-signaled, one-level-deep reference table: each of the five topics pairs a real bundle file (all five exist in references/) with a 'Load When' condition (e.g., 'Records, pattern matching, nullable types' → references/modern-csharp.md). No nesting beyond one level, no reference-shaped content inlined in SKILL.md, and every bundle file is discoverable from the body — matching anchor 5 exactly.

Specificity

The description lists five distinct concrete actions — 'Builds REST APIs using minimal or controller-based routing, configures database access with Entity Framework Core, implements async patterns and cancellation, structures applications with CQRS via MediatR, and scaffolds Blazor components with state management' — which comprehensively covers the declared domain. It exceeds the anchor-4 example (three actions, minor gaps); the only uncovered trigger terms (MAUI, SignalR) are invocation keywords rather than claimed capabilities, so this is not a meaningful coverage gap.

Completeness

Both questions are answered explicitly: a clear 'what' ('Builds REST APIs... configures database access... implements async patterns...') and a concrete 'when' ('Use when building C# applications with .NET 8+, ASP.NET Core APIs, or Blazor web apps. Invoke for C#, .NET, ASP.NET Core, Blazor...'). This matches the anchor-5 example structure exactly; anchor 4 would require the 'when' to be less explicit or specific, which it is not.

Trigger Term Quality

The explicit trigger list — 'C#, .NET, ASP.NET Core, Blazor, Entity Framework, EF Core, Minimal API, MAUI, SignalR' — includes a synonym pair (Entity Framework / EF Core) and the natural terms users would say. It falls short of anchor 5 because common variations are missing (e.g., 'Web API', 'Razor', 'dotnet', '.cs'), while it is clearly better than anchor 3's 'relevant keywords but missing common variations' with no synonyms.

Distinctiveness Conflict Risk

A clear niche (C#/.NET 8+ ecosystem) with distinct, unambiguous triggers (C#, ASP.NET Core, Blazor, EF Core, MAUI, SignalR) that would not naturally fire a generic or adjacent skill. Anchor 4 ('minor overlap risk with closely related skills') does not apply — the ecosystem-specific keywords make mis-triggering unlikely.