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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive behavior, so the bar is lower. The description adds genuinely new context: the $0.01 USDC x402 payment requirement and that the result is probabilistic ('likely gender'), which matters for interpretation. It does not describe the return format or whether a confidence score accompanies the answer.

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 short sentences with no filler: the capability is front-loaded in the opening clause, followed by use cases and cost. Nothing redundant with the title or schema.

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 one-parameter, read-only tool this covers purpose, audience, and cost. However, with no output schema, the description never states what comes back (e.g., 'male'/'female' label, confidence value, null handling for ambiguous names), leaving the return contract underspecified.

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 coverage is 100% and the single parameter is documented, so baseline is 3. The description adds real meaning beyond the schema: the schema says 'First name' while the description clarifies the tool also accepts full names and international names, widening the expected input.

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 and resource: 'determines the likely gender for a first or full name, including international names.' An agent can distinguish this from siblings like interzoid_name_origin or interzoid_fullname_match without opening the schema, though no sibling is named explicitly.

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?

The use-case list (marketing personalization, demographic analysis, salutation selection) implies when the tool is appropriate, but there is no explicit when-not guidance and no routing against adjacent siblings such as interzoid_name_origin or interzoid_identify_language.

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