Conciseness

The body is mostly lean: a rules table, a five-step selection procedure, and three compact correct/incorrect examples, with no padding explaining what OpenTelemetry is. Minor trimmable redundancy keeps it below a 5: step 5 repeats step 1's caveat almost verbatim ("Only create a custom attribute if no registry entry covers the concept" vs. "only create a custom attribute when no registry entry covers the concept"), and the Attribute Registry URL appears twice (in the intro and again under 'Official documentation'). This matches the score-4 anchor ('Efficient; minor instances of over-explanation that could be trimmed') — not 3 because there is no genuinely unnecessary explanation block, and not 5 because the duplication is real.

Actionability

The three code examples are concrete and executable with correct/incorrect contrasts ("span.set_attribute(\"http.request.method\", \"GET\")" vs. "span.set_attribute(\"custom.http.verb\", \"GET\")"), and step 5 gives a concrete naming pattern ("org.namespace.attribute_name"). However, the actual per-domain attribute detail ("HTTP/DB/messaging/RPC attributes" per the rules table) is delegated to ./rules/attributes.md, which does not exist in the provided bundle, so the skill's core deliverable — which registry attribute to use — is not reachable. This matches the score-4 anchor ('Mostly executable guidance; concrete code or commands with minor gaps') — not 5 because the key reference material is missing, not 3 because what is inline is real, executable code rather than pseudocode.

Workflow Clarity

"How to select the right attribute" is a clear, well-ordered five-step sequence, and steps 1–2 ('Search the registry first', 'Check stability') function as checkpoints. It matches the score-4 anchor ('Clear sequence with most checkpoints present; minor validation gaps'): there is no explicit validation/feedback step (e.g., re-verify the chosen attribute against the registry, or how to validate during a version migration). It is not 5 because no explicit verify-and-recover loop exists, and not 3 because the sequence is complete and the checkpoints are more than implicit. The destructive/batch cap does not apply — this is a selection/review task, not a destructive operation.

Progressive Disclosure

The SKILL.md itself is structured well — a Rules table linking "[attributes](./rules/attributes.md)", "[versioning](./rules/versioning.md)", and "[dash0](./rules/dash0.md)" with use cases, plus clearly signaled official documentation links, all one level deep. However, none of the three referenced rule files exist in the provided bundle (no rules/, references/, scripts/, or assets/ directories are present), so every path to the skill's detail layer is broken at the first hop. Per the judging guideline to score against the actual bundle structure, clearly signaled references pointing at missing files leave navigation failing, which sits below the score-4 anchor ('minor organization gaps') and at/below the score-3 anchor ('Some structure but could be better organized'). Not a 4 or 5 because the disclosure model does not actually work when followed; not a 2 because the SKILL.md-level structure itself is well organized and the references are prominently signaled rather than buried.

Specificity

The description lists multiple concrete actions — "selecting, applying, or reviewing telemetry attributes", "attribute migration", "custom attribute decisions" — and enumerates coverage of "the attribute registry, naming patterns, attribute placement, and versioning". This is comprehensive, third-person coverage of the semconv domain with no gaps, matching the score-5 anchor ('Lists multiple specific concrete actions; comprehensive coverage'). It is not a 4 because nothing in the domain's core activities (selection, application, review, migration, naming, placement, versioning) is missing.

Completeness

It explicitly answers both questions: what ("OpenTelemetry Semantic Conventions expert... Covers the attribute registry, naming patterns, attribute placement, and versioning") and when ("Use when selecting, applying, or reviewing telemetry attributes. Triggers on tasks involving attribute selection, semantic convention compliance, attribute migration, or custom attribute decisions"). Both are explicit and concrete, matching the score-5 anchor. It is not a 4 because the 'when' is not merely present but spelled out with multiple concrete trigger phrases.

Trigger Term Quality

Keywords like "telemetry attributes", "attribute migration", and "attribute registry" are natural user phrasings, but the coverage misses common variations users would actually type: "otel attributes", "span attributes", "resource attributes", and looser phrasings like "naming convention". Phrases such as "semantic convention compliance" and "custom attribute decisions" skew formal rather than natural. This fits the score-4 anchor ('Good keyword coverage; a few natural terms missing') — not 5 because synonyms users commonly say are absent, not 3 because the core trigger vocabulary is present and relevant.

Distinctiveness Conflict Risk

The skill occupies a clear niche (OpenTelemetry semantic-convention attributes) and actively reduces conflict risk by deflecting the nearest neighbor: "For span names, span kinds, and span status codes, see the otel-instrumentation skill." This is distinct triggers with minimal conflict risk, matching the score-5 anchor; it is not a 4 because the boundary with the closest overlapping skill is explicitly drawn rather than merely implied.