list_voices

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

With no annotations, the description carries full burden. It discloses the output schema (account and profiles keys, along with voice fields) and that it returns both types, which is meaningful behavioral context. It doesn't explicitly mention read-only behavior, but 'list' strongly implies it.

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 three concise lines: a clear purpose statement, a structured return format description, and a practical usage hint. There is no wasted wording, and the most important information is front-loaded.

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 simple list tool with no output schema, the description fully covers the return structure and how to use the results with generate_speech. It also notes the inclusion of profiles, which is a key behavioral detail. No significant gaps for 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?

The tool has zero parameters, and the baseline for 0 params is 4. The description correctly adds no parameter information since none are needed, and the schema covers the empty parameter set completely.

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 clearly states the tool lists ElevenLabs voices plus saved speech profiles, which is a specific verb+resource. It distinguishes itself from siblings like list_profiles by explicitly including both account voices and profiles, and it provides the return structure with field names.

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 provides downstream usage guidance (how to use a voice or profile name with generate_speech), but it does not explicitly say when to use this tool instead of siblings like list_profiles. The usage context is implied rather than explicitly contrasted with alternatives.

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