Conciseness

The body is lean and assumes competence — no explanations of what music generation or ffprobe are, and every section is directive. It falls short of the 5 anchor because time-sensitive details ("currently $0.04/request", "$0.08/request", adapter "currently ... locked to `lyria-3-pro-preview`", current resolver precedence) are stated inline rather than confined to the dated reference, and a few checklist lines restate earlier sections. It is clearly above the 3 anchor, which requires unnecessary explanation or notable slack.

Actionability

Fully executable guidance throughout: a copy-paste `ffprobe` command with exact flags and JSON output, a verbatim instrumental-only constraint block, a fully specified 9-point prompt structure with ordering, concrete vocal/lyric contracts with section labels, and specific auth error codes (`403`, `API_KEY_SERVICE_BLOCKED`) with an explicit credential-precedence rule. The 4 anchor's 'minor gaps' fit worse than the 5 anchor's copy-paste-ready coverage of the common cases (underscore, full song, vocals).

Workflow Clarity

The 8-step Required Workflow is clearly sequenced with explicit validation checkpoints ("Probe the actual file and listen before recording duration, format, or approval metadata"), feedback loops for error recovery (retry treated as a billable regeneration; "Do not spend retries on permission failures. Resolve the credential/project path first"), and a closing Quality Checklist. This matches the 5 anchor's validation + feedback-loop + checklist profile; the destructive/batch cap does not apply since probing and auditioning are mandated.

Progressive Disclosure

The body is a genuine overview that defers API shape, pricing detail, and prompt templates to a single one-level-deep reference, clearly signaled with when-to-read conditions ("Read [references/api-and-prompting.md](references/api-and-prompting.md) when choosing a model, designing vocals or custom lyrics, using image inputs, debugging the response, or checking current limits and pricing"). The reference file exists, is well-organized, and contains no nested .md references (only external links), matching the 5 anchor.

Specificity

The 'what' is "Generate and validate music with Google Lyria 3 through the Gemini Interactions API" — the domain is named with exactly two concrete actions, matching the anchor for 1-2 concrete actions but not comprehensive coverage (e.g., no mention of prompt design, model selection, or output verification as capabilities). It is below the 4 anchor because the action list is minimal, and above 2 because both actions are specific rather than generic.

Completeness

Explicitly answers both questions: what — "Generate and validate music with Google Lyria 3 through the Gemini Interactions API"; when — "Use before calling OpenMontage `google_music`, designing Lyria 3 Clip or Pro prompts, using image-to-music or custom lyrics, choosing between Lyria 3 and Lyria RealTime, diagnosing Google music-generation failures, or preparing exact-duration music for a video." This matches the 5 anchor's clear what-and-when with concrete trigger phrases; the 4 anchor ('when could be more explicit') fits less well given six explicit trigger scenarios.

Trigger Term Quality

Strong natural triggers: "OpenMontage `google_music`", "designing Lyria 3 Clip or Pro prompts", "image-to-music", "custom lyrics", "choosing between Lyria 3 and Lyria RealTime", "diagnosing Google music-generation failures", "exact-duration music for a video". A few common phrasings are missing (e.g., "soundtrack", "background music", "underscore", "song"), so it falls short of the comprehensive-synonym coverage of the 5 anchor but is well above the 3 anchor's 'missing common variations'.

Distinctiveness Conflict Risk

A clear niche (Lyria 3 music generation via a specific API and tool) with distinct triggers like `google_music`, Lyria 3 Clip/Pro, and Lyria RealTime; it also actively disambiguates sibling skills ("choosing between Lyria 3 and Lyria RealTime"). Minimal overlap risk with generic music or audio skills, matching the 5 anchor.