List voices for text-to-speech

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds genuinely useful non-obvious context: cloned voices resolve to voice_user_id rather than voice_id, and cloning happens in the CraftStory app, not via the API. It omits pagination/ordering/size limits, keeping it from a 5.

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, front-loaded with what the tool returns, then the parameter branch, then the constraint about where cloning occurs. No filler; every clause carries information.

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?

No output schema exists, so the description carries the return-value burden, and it does so by naming the fields and the id mapping. With one optional param fully documented and annotations covering the safety profile, nothing material is missing.

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% and there is only one optional boolean, so the baseline is 3. The description goes beyond the schema's 'also return the account's cloned voices' by explaining that those voices are used as voice_user_id, adding real semantic value about the parameter's effect.

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 voices) and enumerates the returned fields (id, name, language, gender), making it clearly distinct from siblings like list_models and list_avatars. It also pins down the exact downstream parameter each voice type feeds, which is unusually precise.

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 states the condition that selects the cloned-voice branch (include_cloned=true) and cross-references create_audio_clip as the consumer. It lacks an explicit 'when not to use this' or a named alternative among siblings, so it falls short of a 5.

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