List voices for text-to-speech

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

With no annotations, the description carries the full burden, and it does disclose real behavioral context: the two distinct ID namespaces (voice_id vs voice_user_id) and the out-of-band cloning limitation. It omits pagination, ordering, and whether library voices are account-scoped, which are the remaining gaps for a read-only list.

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 tight sentences with zero filler, lead sentence front-loads what is returned, and each subsequent sentence covers exactly one new fact (the flag, the cloning limitation). Nothing is redundant with the tool name or title.

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 one-parameter read tool with no output schema, the description compensates by naming the returned fields and the two ID namespaces. Only pagination/ordering behavior and error cases are unaddressed, which is a minor gap at this complexity level.

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 100%, so baseline is 3, but the description adds meaning the schema does not: that the cloned voices surfaced by include_cloned are addressed by voice_user_id rather than voice_id. That mapping is operationally essential and is absent from the boolean's own description.

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+resource (list library voices) and immediately enumerates the returned fields (id, name, language, gender), then ties each ID type to its downstream consumer (voice_id in create_audio_clip, voice_user_id for cloned voices). An agent can distinguish this from list_avatars and list_models without opening any schema.

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?

Explicitly tells the agent how to reach cloned voices (include_cloned=true) and which parameter to pass the resulting IDs into, plus a negative constraint: voices are cloned in the CraftStory app, not via the API, which prevents a futile search for a clone tool. It stops short of naming an alternative tool or exclusion conditions.

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