Conciseness

The body is mostly dense, novel R3-specific material, but contains noticeable padding: the 'Canonical sources' block and the closing 'Additional Resources' section repeat the same three links, and the five-point 'Why R3 Exists' rationale could be tightened — matching the 3 anchor ('mostly efficient but includes some unnecessary explanation or could be tightened') rather than 4.

Actionability

Concrete, syntactically valid C# throughout with captured verified outputs, an install command, an AwaitOperation dispatch table, and DO/DON'T lists; minor gaps remain since several snippets depend on undefined surrounding context (model, _api, Render, Handle, source), matching the 4 anchor rather than fully copy-paste-ready 5.

Workflow Clarity

Coherent conceptual sequence (when to use → install → quick start → verified core behaviors → concurrency → scheduling → DO/DON'T checklist) with unambiguous guidance for composing pipelines, but it is a reference-style skill without multi-step checkpoints or validation loops, fitting the 4 anchor; the simple-skill exception (under 50 lines) does not apply at ~270 lines.

Progressive Disclosure

The in-body structure is good and the three references are clearly signaled and one level deep, but scored against the actual bundle the referenced files (rx-net-differences.md, async-and-integration-patterns.md, scheduling-and-concurrency.md) are missing from the bundle entirely, making the promised detail inaccessible — more than a minor organization gap (4) though the organization itself is above the minimal-structure anchors.

Specificity

The description enumerates multiple concrete capabilities — 'the Observable<T>/Observer<T> model', 'the OnErrorResume error contract', 'async dispatch with AwaitOperation', 'Task/IAsyncEnumerable integration', 'TimeProvider/FrameProvider scheduling', 'the concurrency contract' — giving comprehensive coverage of what the skill covers, matching the 5 anchor rather than 4 (no coverage gaps of note).

Completeness

The 'what' is clear and detailed, but there is no 'Use when...' clause or equivalent explicit trigger guidance; 'when' is only weakly implied by 'Build reactive/event-driven C#', so per the rubric guideline completeness is capped at 3.

Trigger Term Quality

Good natural keyword coverage ('reactive', 'event-driven', 'C#', 'Observable', 'System.Reactive', 'Rx.NET') including synonyms, but a few natural terms users would say are missing — operator names like 'debounce', 'throttle', 'merge', and 'UniRx' — matching the 4 anchor rather than comprehensive 5.

Distinctiveness Conflict Risk

Clear niche (R3 specifically, explicitly contrasted with 'System.Reactive (Rx.NET)') with distinct trigger terms; minimal conflict risk with other skills.