Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover readOnly/idempotent/non-destructive/closed-world, but the description adds genuinely non-obvious behavior: two result classes (fit='native' vs 'cutdown'), the sign convention of delta_s, the licence_ref vs ref distinction, and that a cue without a listen_url cannot be auditioned. It also discloses that the brief is matched on Songs To Your Eyes' own servers and never sent to a third-party AI service, a privacy trait annotations cannot express.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Purpose is front-loaded in sentence one and the paragraphs are logically ordered (what it does → result kinds → field meanings → operational/privacy note). The catalogue clause in sentence one is dead weight and the listen_url paragraph is slightly over-explained, but overall it is tight and every other sentence earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description carries the burden of return-value explanation and does so for the key fields (fit, delta_s, licence_ref, ref, listen_url), which is a lot for an 8-parameter tool. It omits pagination behavior for limit and does not enumerate the remaining result fields, so it is strong but not exhaustive.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so every parameter (brief, limit, moods, composer, has_vocals, target_seconds, include_previews, tolerance_seconds) is already documented, and the baseline is 3. The description's added richness (fit, delta_s, licence_ref/ref) concerns returned fields rather than the inputs, so it does not meaningfully extend parameter semantics beyond the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

It states a specific verb+resource (finds cues matching an exact runtime) with concrete examples (30-second advert, 90-second title sequence), which cleanly separates it from stye_search_tracks and stye_find_similar. However, the trailing clause 'or anything about the Songs To Your Eyes catalogue' blurs its scope and overlaps the stye_about sibling, slightly diluting an otherwise precise statement.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives clear triggering context — use it when you have a cut of known length — which is exactly the condition that selects this tool. It never names an alternative or an exclusion (e.g. when to prefer stye_search_tracks), so it stops short of full routing guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.