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

With no annotations provided, the description carries the full burden of behavioral disclosure. 'List' implies a read-only operation, which is a useful safety signal, but the description does not reveal what exactly is returned (e.g., voice IDs, names, metadata) or whether 'available' depends on context. It is minimally transparent but not misleading.

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?

The description is a single, front-loaded sentence with no filler. Every word is necessary, and it conveys the complete purpose efficiently.

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 zero-parameter, read-only listing tool with no output schema, the description is almost sufficient. It states the action and the resource. The only minor gap is not specifying the exact format or granularity of the returned voice list, but given the simplicity of the tool, this is a minor omission.

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 has 0 parameters, so there are no parameter semantics to clarify beyond the empty schema. Per the rubric, a zero-parameter tool receives a baseline 4, and the description adds no conflicting or unnecessary parameter info. Nothing more is needed.

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 'List available TTS voices' states a specific verb ('List') and a precise resource ('available TTS voices'). It is clearly distinct from sibling tools like echo_tts, echo_beacon, or echo_order, which are different operations entirely, so an agent can immediately identify its purpose.

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?

The tool's use case is implied by its name and description: if an agent needs to discover which TTS voices exist, this is the tool. However, it gives no explicit guidance about when to prefer it over alternatives (e.g., whether it should be called before echo_tts) and no exclusions. The context is clear by itself but not stated.

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