Conciseness

The body is dense and efficient — payload tables, terse attack sections, and concrete HTTP examples dominate, with no concept tutorials. Minor trimmable content exists: editorializing ('the single highest-paying ATO vector'), brief restatements of known concepts (what state binding and PKCE are), and mild redundancy between the ATO chain in section 2.9 and the PoC pattern. Not 5 (a few tokens don't earn their place), not 3 (padding is minor, not a pattern).

Actionability

Mostly executable guidance: a runnable curl command for .well-known/openid-configuration, a copy-paste redirect_uri bypass payload table, concrete POST /token request bodies, and a systematic PoC procedure naming the exact parameters to fuzz. Minor gaps: several examples use template placeholders (client_id=..., code=<stolen_code>) and there is no complete end-to-end exchange example. Not 5, not 3 — well above 'pseudocode' level.

Workflow Clarity

A clear sequence is present: map the flow (section 1) → attack surface (section 2) → a numbered 4-step PoC pattern with an evidence-capture checkpoint ('on any deviation ... capture as evidence') → severity calibration (section 5). Not 5 because there is no explicit validation step for confirming impact or ruling out false positives before assigning severity; not 3 because checkpoints are present, not merely implicit.

Progressive Disclosure

Good structure: numbered sections, a dedicated Cross-references section with clearly signaled one-level-deep pointers, and a Tools section. Not 5 because it is a single ~157-line monolithic file (above the under-50-line simple-skill exception) with content such as the severity table and known-exemplar lists that could live in a reference file, and the cross-referenced paths point outside this bundle (no references/, scripts/, or assets/ exist). Not 3: structure and navigation are solid.

Specificity

The description enumerates seven concrete, named attack techniques ('redirect_uri bypass, state CSRF, code leak via Referer, response_type confusion, PKCE downgrade, scope creep, ATO chains'), giving comprehensive coverage of the OAuth attack domain. It is not 4 because there are no meaningful gaps in technique coverage.

Completeness

The 'what' is clear and specific (the enumerated attack techniques), but the description itself contains no 'Use when...' clause — trigger guidance exists only as a separate metadata.when_to_use keyword list, which is weakly explicit rather than an explicit when-to-use statement in the description. Per the guideline, a missing 'Use when' clause or equivalent caps completeness at 3.

Trigger Term Quality

Good keyword coverage ('OAuth 2.0', 'OIDC', 'redirect_uri', 'state', 'PKCE') that matches what a user testing an OAuth flow would say, but natural synonyms are missing — 'ATO chains' is jargon where 'account takeover' spelled out would be more natural, and phrases like 'social login' or 'sign in with Google' are absent. Not 5 (synonyms/variations missing), not 3 (coverage is well beyond 'some relevant keywords').

Distinctiveness Conflict Risk

A clear niche with distinctive technique-level triggers ('PKCE downgrade', 'redirect_uri bypass') that are unlikely to fire for unrelated skills. Not 5 because 'ATO chains' and general OAuth surface overlap with sibling skills referenced in the body (ato-methodology, jwt, open-redirect).