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

No annotations are supplied, so the description carries the full behavioral burden and largely does not meet it. It does not state determinism, the formula used, units, output format, or the payment/trial mechanics beyond a mention of 5 free calls. Only the pricing hint adds anything an agent could not infer.

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?

Very short and front-loaded with the subject, which is good. But the second sentence is marketing/pricing boilerplate that consumes half the text while omitting everything an agent actually needs.

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?

No output schema, no annotations, and two undocumented parameters: the definition should explain units, expected input format, and what is returned. It instead supplies only a restated title and a trial-call note, leaving the agent unable to call it confidently beyond guessing from parameter names.

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 0% – both parameters are bare strings with no documentation, and required is empty. The description says nothing about majorRadius or minorRadius: not their meaning, not whether they must share units, not whether strings are parsed as numbers, and not whether they are optional. With zero coverage the description had to compensate and does not.

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?

"Volume of torus" restates the tool name (Torus Volume) rather than adding information, though together they do identify the specific computed quantity and implicitly separate it from the sibling x402-torus-surface. No verb, no specification of formula, units, or input meaning. Vague-but-identifiable rather than clear.

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?

No guidance on when to use this versus alternatives. The only extra sentence concerns free trial calls per signed wallet, which is billing context, not usage guidance. An agent gets no help distinguishing it from the many other geometry/volume tools in the sibling list.

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