List Driver Voices

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

Annotations already declare readOnly, idempotent, and non-destructive, so the description need not repeat these. It adds valuable context about the data semantics (e.g., `language` derivation and conflict rule, `accent` matching requirement) and clarifies the limitation of `voice_instructions`, going beyond the structured annotations.

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 longer than typical, but it earns its length with structured bullet points and front-loaded purpose/usage statements. Every sentence adds meaningful guidance, and the format aids readability despite the density.

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?

Given the tool has no parameters and an output schema exists, the description is fully complete for an agent to invoke it correctly. It covers the key concepts (voices, profiles, languages), selection criteria, and integration with create_or_update_driver, leaving no critical gaps.

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, so the baseline is 4. The description compensates by thoroughly explaining the output fields (language, accent, gender) and their intended use, which is more relevant than parameter docs for this read-only list operation.

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 opens with a specific verb+resource+scope: 'Discover the voices, voice profiles, and languages available for configuring voice-capable drivers.' It clearly distinguishes the tool from sibling list tools by focusing on voice configuration and explicitly references create_or_update_driver, making its purpose 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?

Provides explicit when-to-use guidance: 'Call this before create_or_update_driver when building a voice agent simulation, so you can pass valid `voice`, `voice_profile`, and `language` values.' It also offers selection guidelines and a direct exclusion ('writing accent instructions into `voice_instructions` does NOT change the TTS voice'), effectively preventing misuse.

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