list_voices

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

There are no annotations, so the description carries the full burden of behavioral disclosure. It accurately conveys that the tool lists voices and is non-destructive ('List all available TTS voices'), but it does not describe the return format, whether voice IDs are included, or how providers are represented. For a simple read-only list operation, this is adequate but not rich.

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 two short sentences with no filler. The first sentence states the core function, and the second sentence provides valuable usage context ('before generating TTS'). Every word earns its place.

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?

This is a simple, zero-parameter list operation with no output schema and no annotations. The description explains what it lists, the scope ('across all providers'), and when it is useful. It could mention the return structure, but the simplicity of the operation keeps the definition reasonably complete.

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 input schema has zero parameters, and schema description coverage is 100% since there are no properties. With 0 params, the baseline is 4, and the description correctly implies that no input is needed. The description does not need to add parameter details because there are none.

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 uses a specific verb and resource: 'List all available TTS voices across all providers.' It clearly distinguishes itself from generation tools like generate_tts by focusing on discovery rather than generation. The purpose is immediately obvious and unambiguous.

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 description states when to use it: 'Useful for choosing a voice before generating TTS.' This gives clear context about the intended workflow stage. It does not explicitly name alternatives or exclusions, but the no-parameter scope and unique purpose among siblings make the usage guidance sufficiently clear.

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