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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, open-world). The description adds real value beyond them: the 'lib:' vs 'acct:' voice-source distinction, the note that acct voices are unavailable for Film, and the fact that no credits are charged. It does not disclose pagination behavior beyond naming nextCursor.

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?

Three short sentences, front-loaded with the action and followed by return fields and source semantics. The 'lib:'/'acct:' shorthand is dense and mildly cryptic but each sentence carries information.

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?

With an output schema present, the description needn't enumerate return values, yet it does anyway alongside useful domain context about voice sources and cost. Annotations cover safety; the remaining gap is routing to alternative voice tools.

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?

Schema description coverage is 100%, so the schema already documents limit, cursor, search, and artistId with ranges and meaning. The description adds nothing parameter-specific, so the baseline 3 applies.

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?

States a specific verb and resource: 'Searches the voice library's ready-made voices.' The 'ready-made' qualifier implicitly distinguishes this from sibling operations like studio_artist_voice_record or studio_artist_ready_made_choose, but no sibling is named explicitly, so the agent must infer the boundary.

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?

Usage is implied (search the library to find a voice for a cast artist) but there is no explicit when-to-use versus alternatives such as studio_artist_voice_choose or studio_artist_ready_made_choose. The 'No speech generation or credit charge' line sets expectations but is not routing guidance.

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