check_domain_availability

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile (a safe, non-mutating external lookup) is covered. The parenthetical '(data is true when available)' adds a small interpretation hint, but since an output schema exists it largely restates the return contract rather than revealing traits annotations don't cover, such as latency, caching, or rate limits.

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?

A single tight sentence with the action front-loaded and no filler. It is appropriately sized for a one-parameter lookup, though the trailing parenthetical is slightly redundant with the output 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 simple one-parameter read tool whose annotations convey the safety profile and which ships an output schema, the description covers the essentials. The only real gap is absent usage/routing guidance, which is minor at this complexity level.

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 100% and the single 'domain' parameter is fully documented in the schema with an example and a validation pattern. The description adds no syntax, TLD, or formatting detail beyond what the schema already provides, so the baseline of 3 applies.

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 ('Check') plus resource ('domain name') and the exact outcome ('free to register'), so an agent immediately knows this is an availability lookup rather than a registry read like get_domain. It does not explicitly name a sibling, but the purpose is unambiguous on its own.

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?

There is no when-to-use, when-not-to-use, or alternative guidance. The description never mentions how this differs from get_domain or when a caller should choose it over the domain-listing tools. The intended use is only implied by the verb.

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