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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and a closed world, so the safety profile is fully covered. The description adds that the lookup can resolve to 'listed, rented or not held' — useful negative-result context — but says nothing about auth, rate limits, or caching. The remaining detail is return-value content, which the output schema already carries.

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 front-loaded sentence opens with the verb and resource, then lists the returned data, then closes with the usage trigger. The semicolon-chained clause is dense and slightly run-on, but every clause carries information and nothing is padded.

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 single-parameter read tool with a full output schema and complete annotations, the description covers purpose, trigger, and result scope adequately. The only gap is the absence of guidance relative to the overlapping price/status siblings.

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?

With one parameter and 100% schema description coverage, the schema already explains the 'host' input, including that URLs and bare hosts both work. The description adds no syntax, normalization, or IDN guidance beyond that, so this is the baseline case.

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 — 'Looks up one domain name' — and enumerates exactly what is retrieved (listing status, 12/6/1-month prices, renewal floor and ceiling, appraisal, rent URL). The singular 'one' implicitly contrasts with the sibling search_names, so an agent can route between them without opening a schema.

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?

'call it when the user names a specific domain' gives a clear, explicit trigger condition tied to user intent. It does not, however, address overlap with get_lease_terms or get_rent_status, which appear to surface some of the same price/status data, so the agent gets no exclusion rule for those siblings.

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