Conciseness

The body is lean and dense — prohibitions, a numbered procedure, skip conditions, and an output spec — with no padding explaining concepts Claude already knows; every section earns its place.

Actionability

Gives concrete executable guidance: exact package paths, commands like 'pnpm --filter <package> test <path>', the setupTestDatabase()/setupForDialect() utilities from tests/utils/test-db.ts, and a precise test-naming convention.

Workflow Clarity

The seven-step procedure is clearly sequenced with explicit validation checkpoints ('confirm it fails for the reason the user reported, not for an unrelated setup error', 'Confirm the failure mode matches') and an error-recovery loop that lowers confidence on adjacent failures.

Progressive Disclosure

A compact single-file skill with no external references and well-organized sections (prohibitions, procedure, skip, output); per the rubric this qualifies for a top score without bundle files.

Specificity

Lists multiple concrete targets ('REST handlers, CLI, MCP, migrations, schema registry, or build tooling') and a concrete preferred action ('Prefer a failing vitest test in the affected package').

Completeness

Clearly states what the skill does, but lacks an explicit 'Use when...' trigger clause; per the guidelines a missing explicit trigger caps completeness at 2.

Trigger Term Quality

Contains relevant domain terms (CLI, migration, REST handlers) but leans on internal jargon ('EmDash', 'agent-browser', 'schema registry') rather than natural user phrasing, and omits common variations.

Distinctiveness Conflict Risk

The 'below the browser layer' / 'No agent-browser' scoping plus the enumerated subsystem niche make it clearly distinguishable and unlikely to trigger the wrong skill.