Check domain availability

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

Annotations already mark this as read-only and non-destructive. The description adds beyond that by disclosing the 90-requests-per-minute rate limit, the multi-TLD batch behavior, and the one-TLD requirement for alternatives. This is useful operational context that annotations do not provide.

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?

The description is compact and front-loaded with the core purpose. Each sentence adds either an operational constraint, a rate limit, or a usage recommendation. Some minor redundancy with the schema exists, such as the TLD format note, but overall it is well structured and not bloated.

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 simple read-only availability check, the description covers the essential operational details: multi-TLD support, alternatives behavior, TLD formatting, rate limit, and the intended purchase-verification use case. It does not describe the exact response shape, but no output schema exists and the tool's purpose makes the return intent clear enough.

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%, so the baseline is 3. The description adds meaningful extra semantics, especially for with_alternatives: it clarifies that alternatives are only returned when exactly one TLD is provided and the flag is true. It also reinforces the no-leading-dot TLD format with examples.

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 clearly states the verb and resource: 'Check availability of domain names across multiple TLDs.' It also frames the purpose as verifying availability before purchase, which distinguishes it from domain suggestion tools like domains_suggestDomainNamesFromADescriptionV1, though it does not explicitly name those alternatives.

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 description gives clear context: use before purchase, support for checking multiple TLDs at once, and the specific condition for using with_alternatives (single TLD and set to true). It does not explicitly state when not to use this tool or name alternatives, but the provided usage context is strong.

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