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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the safety profile is covered. The description adds useful content scope (pricing, previews, credits, refund guarantee), but says nothing about the form of the answer (static doc text vs. computed values) or whether it depends on the currently selected voice.

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?

One sentence, front-loaded with the core purpose and followed by a tight enumeration of covered topics. It is slightly list-heavy, but every item (pricing, previews, credits, refund) tells the agent something concrete about the content.

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 parameterless, non-destructive documentation tool with no output schema, the description covers what it returns and its theme adequately. Minor gap: it doesn't state the answer format or that it is voice-agnostic, but nothing blocks 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?

The tool takes zero parameters, so there is nothing for the description to disambiguate; the baseline for a 0-param tool is 4. Schema coverage is 100% with an empty properties object, so no parameter gap exists.

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 states a concrete deliverable: the steps from a chosen voice to a downloaded audio file, plus the topics covered (pricing, previews, credits, refund guarantee). It is clear this is an informational/how-to resource, though it never explicitly contrasts itself with procedural siblings like estimate_cost or get_voice.

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 only implied — an agent can infer you'd call this before ordering a paid generation, but there is no stated when-to-use, no ordering relative to estimate_cost or get_voice, and no exclusions. The scope list hints at what questions it answers, which is weak but real guidance.

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