Conciseness

The body is efficient and assumes Claude's competence — it explains only the non-obvious exp/vmhost mechanics (host/guest split, endpoint wiring, snapshot semantics, audio stream lifecycle) rather than background Go or Ebitengine concepts. It falls at anchor 4 rather than 5 because of a pinned time-sensitive commit ("Targets ebiten commit 7de1780bd (2026-09-27)" outside any old-patterns section) and some redundancy between the recipe and the 'How the driver drives the guest' section that could be trimmed.

Actionability

Guidance is fully executable: copy-paste bash commands with all flags ("go run ./skills/run-ebitengine-app-headless/_driver -pkg ./examples/rotate -ticks 60 -out /tmp/frame.png"), complete Go injector snippets, an exact pixel-offset formula ("the center pixel of that physical w*h image is at 4*((h/2)*w + w/2)"), and a concrete failure-capture command ("> /tmp/run.log 2>&1 || cat /tmp/run.log"). The few placeholders (pageCount, nextButtonX) are explicitly framed as template adaptation points.

Workflow Clarity

The recipe (steps 1–4) is clearly sequenced from no-input capture through scripted input, multi-state snapshots, and inspection, and the 'Verifying a run' section supplies explicit validation checkpoints: judge success by PNG presence rather than piped exit status, save full output to a log before diagnosing, confirm both files exist before byte-comparing, plus retry-once guidance for flaky launches and a safe git-worktree pattern for golden baselines. These are genuine feedback loops for a fragile operation.

Progressive Disclosure

Structure is good: well-labeled sections, an out-of-line driver asset ("A host driver lives at _driver/main.go") positioned as a template, and clear internal anchor links ([Ticks and TPS](#ticks-and-tps), [Verifying a run](#verifying-a-run)). It stops at anchor 4 rather than 5 because the ~365-line body inlines several self-contained deep dives (audio stream inspection, gamepad touchpad semantics, the in-repo Go-test alternative) that would fit one-level-deep reference files, leaving the main file dense.

Specificity

The description lists multiple concrete, specific actions — "launches the app as a vmhost guest", "drives it through its ticks faster than real time", "injects keyboard / mouse / touch / gamepad / text input", "reads the rendered frame back as pixels to assert on or dump as a PNG", "observes the audio the app plays" — with comprehensive coverage and no vague filler, matching the anchor 'Lists multiple specific concrete actions; comprehensive coverage' rather than the anchor below (which requires minor gaps in coverage).

Completeness

It explicitly answers both questions: a detailed third-person 'what' ("It launches the app as a vmhost guest… injects… reads the rendered frame back… observes the audio") followed by an explicit trigger clause — "Use when you need input injection, deterministic multi-tick runs, golden-image checks, or audio assertions — for example to…" — with concrete trigger phrases, exactly the anchor-5 pattern.

Trigger Term Quality

Natural user phrasing is comprehensively covered: "test, debug, screenshot", "input injection, deterministic multi-tick runs, golden-image checks, or audio assertions", plus scenario-level triggers like "reproduce an input-dependent bug", "verify behavior after a sequence of clicks or key presses", "check that the right sound plays", and "capture a single rendered frame". This matches the comprehensive-with-synonyms anchor; no natural term is obviously missing.

Distinctiveness Conflict Risk

It opens with a sharply bounded niche — "run an Ebitengine app (anything implementing ebiten.Game) headlessly and programmatically — no visible window and no changes to the app's source" — and every trigger is Ebitengine- or headless-testing-specific, so it is clearly distinguishable from generic run/test/screenshot skills with minimal conflict risk.