Conciseness

The body is lean and assumes Claude's competence: every line is a rule or command, and the only rationale given is information needed to apply the rule correctly ('because it skips android formatters', 'CI fetches the Robolectric jars only for modules with this file'). No padding and no explanations of concepts Claude already knows, so it matches anchor 5 rather than anchor 4's 'minor instances of over-explanation'.

Actionability

Fully executable, copy-paste-ready commands cover the common cases: './mach gradle ktfmtFormat detekt' for a fast feedback loop, './mach gradle [fenix|focus|components:<component>]:assembleDebug' for verification, './mach test <file-name>' / '{fenix,focus,ac,android-components,geckoview}', plus exact config edits ('testImplementation libs.robolectric', 'robolectric.properties with sdk=37'). Alternatives and anti-patterns ('Don't run ./mach test with --auto') are also concrete, matching anchor 5.

Workflow Clarity

Clear decision guidance with explicit trigger conditions and an error-recovery path: run './mach build' only 'when new changes are pulled into the work tree, or if ./mach gradle ... commands do not succeed', and use ktfmtFormat/detekt when lint is too slow for the feedback loop. It falls short of anchor 5 because the content is a set of parallel rules rather than an explicitly sequenced workflow with validation checkpoints, though no destructive/batch cap applies.

Progressive Disclosure

The skill is under 50 lines with no bundle files (no references/, scripts/, or assets/ exist) and three well-organized sections, so the simple-skill guideline applies. Its single reference, 'mobile/android/fenix/docs/Tech-Principles.md', is one level deep, clearly signaled, and points into the target repo rather than creating nested skill references, matching anchor 5's easy navigation.

Specificity

The description names a specific domain ('Android builds or the mobile/ directory') but the only capability stated is the generic category 'Workflow guide' — no concrete actions like building, linting, or testing are listed. It is above anchor 1 (pure abstract language) because the domain is concrete, but below anchor 3, which requires 1-2 named concrete actions.

Completeness

The 'when' is explicit ('when working with Android builds or the mobile/ directory') but the 'what' is vague: 'Workflow guide' names no capability, so it does not reach anchor 4, whose 'what' lists actual actions ('Extract text from PDFs and fill forms'). It is above anchor 2 because a 'when' clause is clearly present, not absent.

Trigger Term Quality

'Android builds' and 'mobile/ directory' are relevant, natural triggers (paralleling the anchor-3 example 'Works with PDF files'), but coverage stops at two terms. Missing common variations users would say: 'fenix', 'focus-android', 'android-components', 'gradle', 'Kotlin', 'lint', 'assembleDebug' — so it falls short of anchor 4's good keyword coverage.

Distinctiveness Conflict Risk

'Android builds' carves a clear, distinct niche with minimal conflict risk, matching anchor 4 ('mostly distinct; minor overlap risk'). Not anchor 5 because the trigger 'the mobile/ directory' is broader than Android and could overlap with a closely related non-Android mobile skill; not anchor 3 because the Android-specific framing is genuinely distinguishing.