Conciseness

The body is dense, instructional, and free of concept explanations Claude already knows — it consists of task tables and loading rules, e.g. "Don't infer support from an extension's name or the existence of a scaffold". Minor trimming opportunities exist: the intro ("Before recommending an extension or writing code, load the applicable bundled reference files") repeats the numbered "Load bundled reference files" section, and bullets like "Keep the work within the user's request" state generic agent behavior. Fits anchor 4's efficient-with-minor-trimmings better than anchor 5's every-token-earns-its-place.

Actionability

For an instruction/routing skill the guidance is concrete: exact per-task file selections ("<references/script-extensions.md> and [build a custom action with a script](...)") and a real command ("Prefer `stripe docs` when available"). It falls short of anchor 5 because several instructions are pointers rather than executable specifics — "Follow the selected guide's prerequisites, scaffolding, testing, and debugging instructions" and "Follow the selected interface's product documentation from the extension-point catalog" — leaving minor gaps, which is exactly anchor 4.

Workflow Clarity

The process is clearly sequenced: select capability via the task tables, then the numbered "Load bundled reference files" steps (select references → follow pointers → read canonical docs), with recovery guidance such as "If an example in a reference disagrees, check the version and follow the applicable canonical documentation" and "state what is unknown or unsupported before proceeding". Not anchor 5 because there are no explicit validate-then-proceed checkpoints in the main flow (e.g., verifying an app builds/tests after changes); not anchor 3 because sequence and several checkpoints are present, and the destructive/batch cap does not apply to a documentation-routing skill.

Progressive Disclosure

The body is a pure routing overview whose bulk content lives in 12 bundled reference files, every one of which is referenced in the task tables and verified to exist. Navigation is one level deep: internal cross-references inside bundle files (e.g., backend.md → authentication.md) are explicitly routed back through the skill's own link list ("Use this skill's direct links to locate those files"), and external canonical docs are clearly separated from bundled references. This matches anchor 5's clear overview with well-signaled one-level-deep references and easy navigation.

Specificity

Concrete actions "Build, modify, or review" are named with a comprehensive enumeration of specific targets ("custom Stripe Dashboard UI, stripe-app.yaml, @stripe/ui-extension-sdk, ... script extensions, extension interfaces, custom workflow actions"), but coverage of the skill's supported actions has minor gaps — scaffolding, testing, debugging, and publishing are handled by the skill yet unmentioned. Not 5 because the action-verb list itself is narrow relative to the skill's full scope; not 3 because far more than 1–2 concrete actions and objects are specified.

Completeness

Both questions are answered explicitly: the "what" is "Build, modify, or review Stripe Apps and extensions using the relevant documentation and reference guides", and the "when" is given through 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" — with concrete trigger phrases throughout. Clearly matches the anchor 5 example pattern; anchor 4's weaker/'when could be more explicit' caveat does not apply.

Trigger Term Quality

Strong natural keyword coverage including the exact manifest filename ("stripe-app.yaml") and SDK package names ("@stripe/ui-extension-sdk", "@stripe/extensibility-sdk") that users would literally paste, plus "custom workflow actions" and "extension interfaces". A few natural terms are missing — most notably "webhooks" (only paraphrased as "react to events"), plus "marketplace" and testing/debugging phrasings — so it fits anchor 4 rather than the comprehensive synonym coverage of anchor 5; it is clearly above anchor 3's partial coverage.

Distinctiveness Conflict Risk

The description occupies a clear niche (the Stripe Apps/extension platform) with highly distinct triggers like "stripe-app.yaml" and "@stripe/ui-extension-sdk" that would almost never appear in a request meant for another skill, matching anchor 5's minimal conflict risk. It is above anchor 4 because the distinguishing tokens are unique artifacts rather than just a named domain with generic overlap risk.