Conciseness

The body is dense with non-obvious repo facts ("no pyke prebuilt" for the x86_64 emulator, the jsDelivr 50 MB cap, "opt-level=2 still SIGBUS'd in go:e2e", "pdf_oxide" rejected not aliased) and explains nothing Claude already knows — matching the score-5 anchor's assumption of competence. It falls one notch below 5 due to verbatim duplication: the wasm-target composition ("no-ort-target + excel-wasm + ocr-wasm + layout-tract + auto-rotate-tract + ner-candle-wasm ... no tree-sitter") appears both inline and again in the aggregate table, and the long android-target member list is inlined in two places.

Actionability

Guidance is fully concrete and executable: the exact CI command (`task verify:feature-parity` / `python3 scripts/ci/check-feature-parity.py crates/xberg/Cargo.toml`), exact feature algebra (`pdf = ["pdf-native"]`), exact config location (`core/config/pdf.rs`), a table of guarded pairs with allowed deltas, and explicit consequences ("adding a feature to `full` without adding it to `windows-target` fails CI"). Per the rubric's instruction-only note, the absence of code is not penalized when guidance is this actionable.

Workflow Clarity

The primary use case promised by the description — adding or wiring a feature — is a multi-step process (assess WASM/Android safety, pick type-only/tract companions, update the relevant aggregates, run the parity guard, check profile implications), but the body never assembles these into a sequence. All the pieces, including a real validation mechanism, are present yet scattered across sections, matching the score-3 anchor ('sequence present but checkpoints missing or implicit') rather than score 4's clear sequence.

Progressive Disclosure

No bundle files exist, so this is a single-file skill; its section headers (ORT-Incompatible Targets, PDF Backend, ORT Variants, Platform-Conditional, Aggregate Sets, CI parity guard, Build Profiles) make it navigable and every repo-file pointer (crates/xberg/Cargo.toml, scripts/ci/check-feature-parity.py) is real and clearly signaled. It sits at score 4 rather than 5 because at 115 lines some self-contained blocks — the CI parity-guard tables and the long aggregate member lists — are inlined where a one-level-deep reference file would keep the overview leaner, and the under-50-line simple-skill exception does not apply.

Specificity

The description enumerates multiple specific, concrete capability areas — "ORT-incompatible targets (WASM, Android x86_64 emulator)", "type-only and tract inference companion features", "WASM/Android-safe variants", "PDF backend", "mutually-exclusive ORT variants", "platform-conditional deps, aggregate feature sets, and build profiles" — comprehensively mirroring every section of the body. It is well above the score-4 anchor ('several specific actions; minor gaps') because coverage is complete for the skill's scope with no vague filler.

Completeness

Both 'what' (first sentence enumerating the feature-flag policy scope) and 'when' ("Load when adding, wiring, or debugging a Cargo feature, or when reasoning about what compiles on ... targets") are explicit with concrete trigger phrases. This is the exact structure of the score-5 anchor example.

Trigger Term Quality

Natural trigger phrases users would actually say are covered: "adding, wiring, or debugging a Cargo feature", "reasoning about what compiles on WASM/Android/Windows/macOS-intel targets", plus synonyms ("feature flags" / "Cargo feature") and platform keywords. It matches the score-5 anchor's comprehensive coverage including synonyms; the score-4 anchor ('a few natural terms missing') understates the breadth.

Distinctiveness Conflict Risk

The niche is sharply distinct — "crates/xberg", ORT vs tract inference, Android x86_64 emulator, jsDelivr-scale WASM constraints — terms no other generic Cargo or feature-management skill would claim. Minimal conflict risk, matching the score-5 anchor.