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

Annotations already declare readOnlyHint and destructiveHint, so safety is covered; the description adds the auth requirement ('needs the read scope') and explains the meaning of the `voiceDescription` field. Good added context beyond the structured data.

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 compact sentences with the resource stated up front, followed by field guidance and then the auth note. Every sentence carries content; structure is slightly loose but far from padded.

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 zero-parameter list tool with no output schema and full annotation coverage, the description is nearly sufficient: it explains what comes back and the access scope needed. It could go one step further by noting whether results are paginated or 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?

Zero parameters, so there is no parameter semantics to explain; this is the baseline-4 case. The description instead clarifies a return field, which is a bonus rather than a gap.

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 resource (the account's actors) and enumerates what it returns: identity, voice, and locked parts. It does not explicitly distinguish itself from the sibling characters_voice, which is the one plausible source of confusion, so it falls short of a 5.

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?

Gives one concrete directive: read `voiceDescription` before designing another voice and reuse the fitting actor. That implies the usage context but names no alternative sibling or exclusion condition, so the when-to-use guidance is only partially covered.

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