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

Annotations already declare read-only, idempotent, closed-world behavior, so the description's job is to add operation-specific context — and it does, disclosing that voiceover results are paged ('a page at a time') and filtered by language and gender, and naming the returned fields. It stops short of stating default page size behavior in prose (that lives in the schema) or describing the response envelope.

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?

Two sentences with the usage trigger front-loaded and no filler; the pricing hand-off is placed at the end where it belongs. The middle clause listing durations, formats and modes is somewhat compressed and reads as a run-on, but nothing is wasted.

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?

For a read-only catalog tool with idempotent annotations but no output schema, the description adequately signals what comes back (models, durations, formats, modes, per-model image fields, voices) and how paging works. Minor gaps remain around response shape and whether non-voiceover types ignore the voiceover-only parameters.

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 coverage is 83% and each parameter already carries its own 'Voice-overs: ...' scoping note, so the schema does most of the work. The description's contribution is consolidating that model/limit/offset/language/gender only matter for the voiceover type and that max_reference_images/start_image/end_image are per-model attributes rather than inputs — useful, but marginal 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?

The description states a specific resource and scope: the models, durations, formats, modes and per-model image fields for image/video/voiceover creations, plus model voices for voice-overs. It is clearly distinguishable from the quote_* family, though the dense compound sentence makes the core identity ('list available creation options') slightly harder to grasp at a glance than the title alone.

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?

It explicitly names the trigger condition ('when you need the choices for a creation before pricing it') and routes the agent away to the alternative ('Exact prices come from the quote_* tools'). That is an explicit when-to-use plus when-to-use-something-else pairing.

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