Conciseness

The body is mostly lean but carries noticeable redundancy: the "What is covered in this Skill?" bullet list restates the Workflow steps almost one-for-one, the Constraints MUSTs ("MUST identify 3-6 functional or workflow layers", "MUST generate 4-5 options per layer", "MUST challenge scope with the smallest-useful-version question") repeat steps 2 and 3, and "When to use this skill" duplicates the frontmatter description's trigger phrases. This matches 'Mostly efficient but includes some unnecessary explanation or could be tightened' — not 4, since the duplication is systematic across three sections rather than a minor trim.

Actionability

For an instruction-only skill the guidance is concrete and executable: fixed counts ("Identify 3-6 functional or workflow layers", "generate 4-5 implementation or quality options ordered from the simplest acceptable choice"), an exact challenge question ("If this had to ship tomorrow, what would be the smallest useful version?"), explicit rejection criteria, and named routing targets (041-planning-plan-mode, 042-planning-openspec, 043-planning-github-issues, 044-planning-jira). Minor gaps keep it from 5: no worked example of a composed slice in the body and routing skills are named but not linked as files.

Workflow Clarity

Six steps are clearly sequenced and step 6 is an explicit validation checkpoint ("Check every slice for value, size, testability, deliverability, and issue-tracking suitability"), which fits 'Clear sequence with most checkpoints present'. It is not 5 because the body lacks a feedback loop for what to do when a slice fails the self-check (no fix-and-retry guidance is stated in the body, only safeguards in the reference file), and not 3 because checkpoints are explicit rather than implicit.

Progressive Disclosure

The body is a concise overview pointing to exactly one reference file (references/052-design-hamburger-method.md), which exists, is one level deep (it contains no further references), and is clearly signaled twice — a MUST-read constraint up front and a dedicated Reference section at the end. The reference file itself covers detailed steps, examples, output format, and safeguards. This matches the top anchor: clear overview, well-signaled one-level-deep reference, easy navigation.

Specificity

The description names its domain ("a large feature, story, plan, or spec idea needs to be split into small vertical slices") and one concrete action (splitting into vertical slices with the Hamburger Method), but does not enumerate several specific capabilities — matching the anchor 'Names domain and 1-2 concrete actions, but not comprehensive'. It is not score 4 because it never lists multiple distinct actions (e.g., mapping layers, composing a first slice, self-checking slices), and not score 2 because the action named is concrete rather than generic.

Completeness

It explicitly answers both questions: what it does ("needs to be split into small vertical slices with the Hamburger Method") and when to use it ("Use when a large feature, story, plan, or spec idea... This should trigger for requests such as..."). This matches the anchor 'Clearly and explicitly answers both what AND when with concrete trigger phrases' — the when clause is explicit and populated with real example requests.

Trigger Term Quality

It provides five varied, natural trigger phrases users would actually say: "Split this oversized story; Find the smallest useful slice; Break this feature into vertical slices; Apply the Hamburger Method; Turn this broad plan into tracked slices" — comprehensive coverage including synonyms (oversized story / broad plan / smallest useful slice). This matches the top anchor for natural-term coverage with variations; no common phrasing family is obviously missing.

Distinctiveness Conflict Risk

The named method ("Hamburger Method") carves a clear niche with distinct triggers, but generic phrases like "Split this oversized story" or "Break this feature into vertical slices" could overlap with other story-splitting/planning skills in the same toolkit ("Part of Plinth Toolkit" implies siblings). This fits 'Mostly distinct; minor overlap risk with closely related skills' rather than 5, since the underlying request pattern is one several decomposition skills could claim.