Conciseness

The body is lean: every line is either a house convention ("Prefer lowercase log-message prose", "Keep public-response sanitization separate from diagnostic reporting") or non-obvious library behavior ("A report's plain Display stops after the first context and omits attachments"). Nothing re-explains Rust or basic tracing concepts Claude already knows, matching the 'every token earns its place' anchor.

Actionability

Guidance uses exact executable syntax — `%error` vs `?report` for Display vs Debug recording, `err` vs `err(Debug)`, `skip(password)`, `fields(user_id = user.id)` — and both code blocks are copy-paste-ready patterns covering the common event and instrumentation cases. This matches the 'fully executable, copy-paste ready, covers common cases' anchor.

Workflow Clarity

This is a simple, single-purpose conventions skill under 50 lines with no multi-step process, and the guidance within each section (Event Recording, Instrumentation) is unambiguous with clear decision rules for choosing between alternatives (e.g., ordinary error vs error_stack::Report). The simple-skill exception applies; there are no destructive or batch operations that would require validation checkpoints.

Progressive Disclosure

The skill is under 50 lines with no external files referenced or needed; the two well-organized section headers (Event Recording, Instrumentation) provide clear structure. Per the rubric's guideline for short skills needing no external references, well-organized sections alone merit the top score.

Specificity

The description names the domain ("tracing and instrumentation practices for Rust") and concrete technical items appear only in the trigger clause ("adding spans, events, or #[tracing::instrument]"), but the capability statement itself offers no specific actions beyond the generic word "practices". It sits between anchor 3 (domain plus 1-2 concrete actions) and anchor 4 (several specific actions), closer to 3 because the 'what' is a label rather than an action list.

Completeness

Both parts are present: the what ("HASH tracing and instrumentation practices for Rust") and an explicit when with concrete triggers ("Use when adding spans, events, or #[tracing::instrument] to Rust code"). It does not reach anchor 5 because the what-clause is generic ("practices") rather than enumerating concrete capabilities like error recording or parameter redaction.

Trigger Term Quality

Terms like "tracing", "instrument", "spans", "events", and "#[tracing::instrument]" are exactly what a user would say when needing this skill, and "for Rust" scopes them. It falls short of anchor 5 because natural synonyms such as "logging" or "log messages" (a very common way users phrase this need) are missing.

Distinctiveness Conflict Risk

The pairing of "for Rust" with "#[tracing::instrument]" and the tracing-specific vocabulary carve out a clear niche with distinct triggers and minimal overlap risk against general logging or observability skills.