Check domain availability

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

Beyond the annotations, the description adds that the call reads only and reserves nothing, that results reflect how registries answer, and that availability here does not imply ordering capability. These are meaningful behavioral disclosures not present in the readOnlyHint/openWorldHint/destructiveHint annotations.

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 sentences deliver the core action, the alternative tool condition, and the key limitation, all without redundancy. The primary behavior is front-loaded, and every sentence earns its place.

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?

With an output schema present and annotations covering the read-only/open-world safety profile, the description supplies the remaining decision-relevant context: what to check, when to use it, when not to, and what an available result means. Nothing critical 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?

Schema coverage is 100%, and the schema already describes body.domainNames as fully qualified names with an example. The description references the same parameter without adding extra syntax or constraints, so the schema carries the semantic weight.

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 specific verb and resource: it checks whether domain names in body.domainNames can be registered and returns per-name availability. It also distinguishes itself from eurodns_domain_get, so an agent can tell this availability-check tool apart from the full-record lookup tool.

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 explicitly says to use it for names not held in the account and directs the agent to eurodns_domain_get instead for domains already in the account. It also clarifies that this server does not register domains, so an available name must be ordered elsewhere, leaving no ambiguity about when this tool is appropriate.

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