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

With no annotations, the description still declares 'Read-only' and enumerates the returned attributes (engine, gender, accent, expressive/Ukrainian support, recommended flag, preview audio), giving a solid picture of what calling it yields. No auth requirements or rate limits are mentioned, but for a zero-param catalogue read those are minor.

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 compact sentences, front-loaded with the resource and channel scope, followed by the cross-reference to the tools that consume voice_id. The field enumeration is dense but justified since no output schema exists.

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?

Absent an output schema, the description compensates by listing the returned fields and the safety profile, which is enough for an agent to call a parameterless read tool correctly. The one gap is the lack of differentiation from the sibling retell-voices listing tool.

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?

The tool takes no parameters, so the baseline of 4 applies; the description does not need to explain any inputs and correctly devotes its space to outputs instead.

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?

Opens with a specific verb+resource and names the three consuming channels (website widget, Slide Presenter, Telegram), then enumerates the fields returned. Clear what it does, though it never distinguishes itself from the sibling list_retell_voices, which is the only other voice-listing tool in the catalog.

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 routes downstream usage: 'Use a voice_id from here in set_agent_voice / set_presentation_voice / set_telegram_voice_settings', which tells the agent exactly why to call it. Missing the negative case — no statement on when to prefer list_retell_voices instead.

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