The body is an efficient index that assumes Claude's competence (it does not explain DI/Scope basics), but the lifecycle-at-a-glance diagram and the 'Stages' list enumerate the same orient→design→implement→test→verify pipeline, and 'How to use this skill' partly restates the opening blockquote. It is mostly efficient but includes some overlap that could be tightened, matching the 'mostly efficient but could be tightened' anchor.

Concrete guidance is present — named stage/topic files with one-line descriptions and concrete red-line imperatives such as 'No `new` on a class whose constructor carries `@IService` deps — inject with `@IX`' — but the executable recipes and code examples are delegated to the referenced stage files rather than given inline, so key actionable detail is incomplete in the body itself.

The stages are explicitly sequenced (orient → design → implement → test → verify) with a stated 'ordered but not strictly linear' caveat and two concrete error-recovery feedback loops ('a test failure ... sends you back to design'; 'a CyclicDependencyError sends you to design.md §dependency-direction and implement.md §cycles'), plus a named Verify stage with lint/typecheck/test checks, matching the clear-sequence-with-feedback-loops anchor.

The body is a clear overview with well-signaled, one-level-deep markdown links to stage and topic files (orient.md, design.md, implement.md, test.md, verify.md, align.md, commit-align.md, server-align.md, plus topic files), each labeled with its scope, matching the clear-overview-with-well-signaled-references anchor. No bundle files were present to verify the referenced paths exist, so this scores the reference structure as written.

The description lists many concrete actions — 'adding or modifying a domain Service', 'choosing a LifecycleScope', 'wiring DI dependencies', 'splitting a domain across scopes', 'owning or migrating a config section', 'gating behavior behind an experimental flag', 'raising coded errors' — matching the anchor for multiple specific concrete actions. The 'Use when developing...' trigger form mirrors the accepted good examples rather than a first/second-person voice, so no voice penalty applies.

It explicitly answers both 'what' ('Self-contained guide organized by development stage (orient → design → implement → test → verify)') and 'when' via an explicit 'Use when...' clause enumerating trigger scenarios, satisfying the anchor for clearly answering both what AND when with explicit triggers.

Natural trigger phrases a developer on this codebase would actually say are well covered: 'Use when developing in packages/agent-core-v2', 'porting business logic from agent-core (v1) to v2', 'triaging a main-branch commit against v2', 'exposing a v2 domain over server-v2'. These are domain-native terms rather than generic jargon, matching the good-coverage anchor.

The niche is tightly scoped to 'packages/agent-core-v2 (the DI × Scope agent engine)' with highly specific triggers (LifecycleScope, DI wiring, v1→v2 porting, server-v2 wire exposure), making conflict with other skills unlikely and matching the clear-niche anchor.