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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so safety is covered. The description adds real beyond-schema behavior: it is a read-only enumeration returning a compact table with display name, id, style tags, current receptionist usage, and a preview link, plus the constraint that only the exact id may be forwarded.

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?

Two sentences, both load-bearing: the first defines output contents, the second defines the downstream contract. No filler and no restatement of the tool name.

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?

There is no output schema, so the description's enumeration of returned fields carries that burden and does so adequately for a zero-parameter list. With annotations covering the safety profile, nothing material is missing for correct invocation.

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 the baseline is 4; there is nothing to disambiguate. The only 'parameter' guidance concerns the downstream updateAgent `voice` field, and the description correctly warns to pass the exact id rather than a display name.

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+resource ('List voices the user can select for a receptionist') and enumerates the exact columns returned. This clearly separates it from mutation siblings like updateAgent and list siblings dealing with calls, contacts, or agents.

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?

Explicitly routes the agent downstream: 'Pass only the exact id to updateAgent `voice`' tells the agent this is the discovery step before an update. It gives clear context but does not state exclusions or when another voice source would be preferred.

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