Conciseness

The body is mostly efficient, but spends tokens on concepts Claude already knows — the 'longest' lifetime function and 'Summary' trait examples are canonical Rust-book basics — plus a persona intro ('Senior Rust engineer with deep expertise...'), a 'Knowledge Reference' keyword dump, and validation commands duplicated between Core Workflow step 5 and the Validation Commands section. Not score 2 because the padding is a minority of the body; not score 4 because the redundant and didactic sections are noticeable rather than minor.

Actionability

Code examples are fully executable and copy-paste ready with imports, covering the common cases (ownership/lifetimes, trait design, thiserror error handling, tokio async), and the cargo commands are exact ('cargo clippy --all-targets --all-features', 'cargo test --doc'). Matches the anchor-5 pattern of executable examples covering common cases.

Workflow Clarity

The Core Workflow is a clearly sequenced 5-step process (analyze ownership → design traits → implement safely → handle errors → validate) with an explicit validation step and a feedback loop ('fix all warnings before finalising'), and the Constraints section acts as a checklist. Not score 4 because validation checkpoints and the fix-retry loop are explicit, not merely present.

Progressive Disclosure

The Reference Guide table cleanly signals five real one-level-deep reference files (all verified present in references/) with per-topic 'Load When' conditions, while the inline content is limited to key patterns rather than inlined reference bulk — matching the anchor-5 pattern of a clear overview with well-signaled references.

Specificity

Lists multiple specific concrete actions — 'Implements ownership patterns, manages lifetimes, designs trait hierarchies, builds async applications with tokio, and structures error handling with Result/Option' — with comprehensive coverage of the Rust domain; not score 4 because there are no meaningful coverage gaps.

Completeness

Explicitly answers both what ('Writes, reviews, and debugs idiomatic Rust code...' with enumerated capabilities) and when ('Use when building Rust applications, solving ownership or borrowing issues, designing trait-based APIs, implementing async/await concurrency, creating FFI bindings, or optimizing for performance and memory safety') with concrete trigger phrases — exactly the anchor-5 example pattern.

Trigger Term Quality

Good keyword coverage with natural terms users would say ('Rust, Cargo, ownership, borrowing, lifetimes, async Rust, tokio, memory safety, systems programming'), but the anchor-5 bar of 'synonyms and file extensions' is not met — '.rs', 'crates', and 'Cargo.toml' are absent. Not score 3 because coverage goes well beyond 'some relevant keywords'.

Distinctiveness Conflict Risk

Clear niche (Rust language engineering) with distinct, domain-specific triggers (ownership, borrowing, lifetimes, tokio); minimal conflict risk with other language skills. Not score 4 because the triggers are unambiguous for this domain.