Conciseness

The body is efficient — lean task tables, short directive paragraphs, and no explanation of concepts Claude already knows (e.g., 'Don't infer support from an extension's name or the existence of a scaffold' assumes competence). Minor trimming is possible: the editorial line 'A link or filename in this skill isn't a substitute for reading its contents' and some overlap between the section intros and the numbered 'Load bundled reference files' steps keep it below anchor 5.

Actionability

For an instruction-only skill the guidance is concrete: exact bundled paths (<references/script-extensions.md>, <references/backend.md>), specific external URLs, task-to-resource tables for each phase, and executable resolution rules ('Resolve references/ paths relative to this skill's directory', 'Prefer stripe docs when available'). It is not fully copy-paste ready in the anchor-5 sense — there is no worked example of, say, fetching a hosted reference — leaving a minor gap.

Workflow Clarity

A clear sequence is present (select documentation → load bundled references → follow pointers → read canonical docs) with an error-recovery rule ('If an example in a reference disagrees, check the version and follow the applicable canonical documentation') and a stop-condition ('state what is unknown or unsupported before proceeding'). It lacks anchor-5's explicit validation checkpoints on the app work itself — testing/debugging is delegated to the referenced guides rather than stated as a checkpoint in the body.

Progressive Disclosure

The body is a pure overview: every one of the 12 referenced files cited in the task tables exists in references/, and cross-pointers between bundled files (verified in the bundle) are at most one level deep, with explicit instructions for resolving them. Navigation via task tables is easy and content is appropriately split, matching the anchor-5 pattern of well-signaled one-level-deep references.

Specificity

The description enumerates several specific capabilities — 'custom Stripe Dashboard UI, stripe-app.yaml, @stripe/ui-extension-sdk, @stripe/extensibility-sdk, script extensions, extension interfaces, custom workflow actions' — going well beyond naming the domain with 1-2 actions. It falls short of anchor 5 only because the action verbs themselves ('Build, modify, or review') remain generic rather than varied concrete operations.

Completeness

It clearly answers 'what' ('Build, modify, or review Stripe Apps and extensions using the relevant documentation and reference guides') and 'when' with two explicit trigger clauses ('Use for custom Stripe Dashboard UI, stripe-app.yaml...' and 'Also use when deciding whether a Stripe extension can support the user's billing or workflow requirements'). Both are present with concrete trigger phrases, matching the anchor-5 example; score 4 would require the 'when' to be less explicit than it is.

Trigger Term Quality

Strong natural keyword coverage including 'Stripe Apps', 'extensions', 'Dashboard UI', 'stripe-app.yaml', 'script extensions', 'custom workflow actions', 'authenticate to Stripe', and 'react to events' — terms users would plausibly say. A few common variations are missing (e.g., 'webhooks' is only implied by 'react to events', and marketplace terminology is absent), keeping it at anchor 4 rather than 5.

Distinctiveness Conflict Risk

The description occupies a clear niche — Stripe Apps/extensions with distinctive triggers like 'stripe-app.yaml' and the two SDK package names — making false triggers for unrelated skills unlikely. The only conceivable overlap is with a generic Stripe-API skill, but the scope is explicitly limited to apps, extensions, and Dashboard UI, which is minimal conflict risk per anchor 5.