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

Annotations already declare idempotentHint=true and destructiveHint=true; the description reinforces idempotency (reconciliation of identical retries) and adds a cost signal ('no model call or credit charge'). But it never says what the destructive overwrite actually replaces for this scene/character, so the destructiveHint is left unelaborated.

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 tight sentences with the core action front-loaded, followed by the revision/operationId contract and then the cost note. No filler or repetition, though the second sentence packs several concepts together.

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 annotations covering safety/idempotency and an output schema handling return values, the description supplies the missing optimistic-concurrency contract (expectedRevision + stable operationId) and the cost profile. Only the destructive consequence of the write is left unexplained.

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 all seven parameters including the useCharacterVoice saved-vs-native semantics. The description only names expectedRevision, operationId and the voice choice, restating schema content without adding format or syntax detail beyond it.

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 names a specific verb (set), resource (speech voice choice), and precise scope (one character in one scene, saved-character vs native), which an agent can act on directly. It stops short of naming the nearest sibling (e.g., studio_artist_voice_choose or studio_film_toggle_sound) to disambiguate, so it is clear but not sibling-differentiating.

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?

It gives useful operational context on retries via identical operationId/input and notes there is no model call or credit charge, which helps an agent decide this is a cheap edit. However, it never states when to prefer this over adjacent voice/toggle tools, nor any prerequisites beyond reading revision.

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