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

Annotations only declare the safe read profile (readOnly, idempotent, non-destructive), but the description adds the crucial interaction model: this renders an interactive gallery, waits for a pick, and returns it as a message naming the Look. That return/round-trip behavior is exactly the kind of trait the annotations cannot express, though latency/blocking expectations are unstated.

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?

Three sentences, zero waste: core behavior first, then when-to-use and the song_id variant, then the return contract. Each sentence earns its place and the most important information is front-loaded.

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 nine fully documented parameters and no output schema, the description provides the one thing the schema can't: what calling this actually produces (an interactive gallery plus a message naming the pick). Nothing essential is missing, though the absence of any latency/interaction-cost note is a minor gap.

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 all nine parameters are already documented in the schema. The description's only param note (song_id previews with an analyzed song) restates what the schema already says, adding no new syntax or format detail. Baseline 3 applies.

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?

States a specific verb ('Shows') and resource ('Looks') plus the distinctive modality: a gallery the person can play and pick from, with each Look playing as the real render. That interactive framing implicitly separates it from list_looks, but the sibling is never named, so an agent must infer the distinction.

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?

Gives a clear triggering condition ('whenever they want to see, browse or choose Looks') and explicitly scopes song_id to previewing with an analyzed song. However, 'browse' overlaps with list_looks and no when-not or alternative is offered, leaving the boundary to inference.

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