Conciseness

The body is ~35 lean lines with zero padding or explanations of concepts Claude already knows; every section (Process, Principles, Conventions, Output) earns its place. The only redundancy is line 8 repeating the frontmatter description, which is too minor to drop it from the 'lean and efficient' anchor.

Actionability

As an instruction-only skill it needs no code, and the guidance is concrete: 'Use the ark-analysis skill', 'Use `?watch=true` query param for SSE streaming (Kubernetes-style)', 'Use named ports (e.g., `port: mcp`)', plus a five-item deliverables checklist. It sits below 5 because steps like 'Identify Patterns - Find existing idioms' stay at the directive level without a worked example of what conformance looks like.

Workflow Clarity

The Process section gives a clearly sequenced five-step flow, and step 5 ('Raise questions on choices that are hard to reverse') functions as a human-in-the-loop checkpoint. It misses 5 because there is no explicit validation or review step confirming the design before the architecture document is produced, and the ark-analysis step's output is never tied into the later steps.

Progressive Disclosure

The skill is under 50 lines, needs no external reference files (verified: no references/, scripts/, or assets/ exist), and is organized into four well-labeled sections, which the rubric's simple-skill guideline scores as 5. The one external mention (ark-analysis skill) is a sibling skill invocation, not a bundle reference.

Specificity

The description names the domain ("Ark features", architecture) and one concrete action ("Design architecture") but never expands into the actual capabilities involved (e.g., producing component diagrams, data models, or phased plans). It matches the anchor 'Names domain and 1-2 concrete actions, but not comprehensive' rather than 4, which requires several specific actions.

Completeness

Both what ("Design architecture for Ark features following existing patterns and principles") and when ("Use when planning new features, extending components, or evaluating technical approaches") are explicitly present, so it exceeds the 3 anchor. It falls short of 5 because the trigger phrases are somewhat generic and the 'what' does not state concrete outputs.

Trigger Term Quality

"planning new features, extending components, or evaluating technical approaches" are natural phrases a user would say. However, common variations like "design doc", "tech spec", "RFC", or "architecture review" are absent, keeping it below the comprehensive-synonym coverage of a 5.

Distinctiveness Conflict Risk

The "Ark features" domain and architecture-design focus form a clear niche distinct from sibling skills like ark-analysis. Minor overlap risk remains because generic triggers such as "planning new features" could fire for general feature-design requests, matching 'Mostly distinct; minor overlap risk with closely related skills' rather than 5.