Conciseness

The body is lean and every line carries non-obvious domain knowledge Claude could not infer: 'MTR is not Monthly Recurring Revenue (MRR)', 'Billing periods are not calendar months', the $2,500 allowance with 'billed 1% of all tracked revenue (invoice amounts are full dollars, rounded down)', and the concrete restricted-feature list. Nothing explains concepts Claude already knows and no section is padded.

Actionability

Guidance is fully executable for an instruction-only skill: exact tool names ('get-account-billing', 'list-account-billing-invoices', 'list-collaborators', 'list-projects'), an explicit anti-pattern ('Do not use rc invoices, which lists a customer's invoices'), a concrete settings URL, and case-based routing (non-owner → contact owner via list-collaborators; enterprise → Customer Success manager). Every common case is covered with specific steps.

Workflow Clarity

This is a simple, single-purpose skill (answer account billing questions) whose action is unambiguous per case: which tool answers which question, and what to do when the user is not the project owner or is on an enterprise plan. Operations are read-only, so the destructive/batch validation cap does not apply; the rubric's simple-skill exception supports a 5.

Progressive Disclosure

The skill is a single self-contained SKILL.md (~60 lines) with no bundle files (references/, scripts/, assets/ absent) and no external files needed. Sections (Use / Context / Pro plan / Invoice details) are clearly headed, all content is appropriately inline at this size, and there are no nested references. Well-organized sections fully satisfy the structure expected at this scale.

Specificity

The description names concrete domain topics ('their RevenueCat plan, billing, their RevenueCat invoices, or how much they will have to pay RevenueCat') but lists no actions the skill performs — no verbs like retrieves, lists, or analyzes. This matches anchor 2 ('Names the domain but actions are minimal or generic'), not anchor 3 which requires 1-2 concrete actions, and not anchor 1 since the domain is specific rather than vague.

Completeness

'Use when the user asks about their RevenueCat plan, billing...' provides an explicit when-clause, but the description contains no what-clause stating what the skill does (e.g., fetching account plan, MTR usage, or invoices). Anchor 2 explicitly covers 'only when is present without what'. It is not 3 because a clear 'what' cannot be scored from what is explicitly stated, per the score-only-what-is-stated guideline.

Trigger Term Quality

Natural phrases users would actually say are present: 'RevenueCat plan', 'billing', 'invoices', and 'how much they will have to pay RevenueCat'. Common variations such as 'charges', 'pricing', 'payment method', or 'MTR' are missing, so it fits anchor 4 ('good keyword coverage; a few natural terms missing') rather than the comprehensive synonym coverage of anchor 5 or the sparser anchor 3.

Distinctiveness Conflict Risk

The 'RevenueCat' scoping plus the account-billing focus (developer's plan/invoices rather than customer subscription invoices, as the body clarifies) give it a clear niche with distinct triggers and minimal conflict risk with other billing or invoice skills — anchor 5.