Conciseness

The body is dense and project-specific throughout — it explains no concepts Claude already knows — but contains genuine duplication: the Room factory rule ("factory = { MeshtasticDatabaseConstructor.initialize() }") appears verbatim in both §3 and §6, and expect/actual restraint plus shared-helper guidance is repeated across §2 and §4. This fits the 4 anchor (minor instances that could be trimmed) rather than 5, where every token would earn its place.

Actionability

Guidance is fully concrete and executable: exact replacement mappings ("ConcurrentHashMap -> atomicfu", "java.io.* -> Okio"), exact API directives ("Use safeCatching {} from core:common", "@Upsert fun putAll(items: List<T>)", "chunk size ≤ 999"), a runnable check command (kmpSmokeCompile), and real file paths. For an instruction-only skill this matches the 5 anchor — copy-paste-ready specifics covering the common cases with no meaningful gaps, so 4 doesn't apply.

Workflow Clarity

Most of the skill is a rulebook, but §8 ("Onboarding a New Target") is a clearly numbered 4-step sequence that includes an explicit verification checkpoint ("Test using kmpSmokeCompile to verify cross-platform compilation"). This fits 4 (clear sequence, most checkpoints present, minor validation gaps); not 5 because there is no error-recovery/feedback loop if the cross-platform check fails, and not 3 because a checkpoint is explicitly present.

Progressive Disclosure

A well-organized single-file skill (~63 lines) with clean section headers and a clearly signaled "Reference Anchors" section pointing to live repo paths; no bundle files exist, so nothing is mis-split. Fits the 4 anchor (good structure, content appropriately placed); not 5 because it slightly exceeds the simple-skill line and sections like §5 (catalog aliases) and §6 (Room patterns) hold detail that could graduate to reference files as the skill grows.

Specificity

The description names several concrete coverage areas — "where commonMain ends", "how expect/actual is bridged", and "the networking, database and platform-integration boundaries" — matching the anchor for several specific items with minor gaps. It falls short of 5 because these are domains/rules rather than a comprehensive list of concrete actions, and above 3 because it goes well beyond naming just 1-2 items.

Completeness

It explicitly answers both "what" (KMP source-set rules, expect/actual bridging, networking/database/platform-integration boundaries for Meshtastic-Android) and "when" ("Use this whenever you add a file to a KMP module, move code between source sets, or hit a compile error that appears on only one target") with three concrete trigger conditions. This matches the 5 anchor; the "when" is already fully explicit, so 4's looser standard doesn't apply.

Trigger Term Quality

It includes natural phrases users would actually say — "add a file to a KMP module", "move code between source sets", "compile error that appears on only one target" — giving good keyword coverage. Not 5 because common synonyms and variations (e.g., "Kotlin Multiplatform" vs "KMP", "multiplatform", file extensions, other targets like desktop/iOS) are missing.

Distinctiveness Conflict Risk

Highly project-specific terms ("Meshtastic-Android", "commonMain", "expect/actual", "KMP module") carve out a clear niche with distinct triggers and minimal conflict risk with any generic skill. Not 4: no closely related skill would plausibly trigger on these phrases.