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

No annotations are provided. The description is transparent about not returning WHOIS/ownership data, and several parameter descriptions mention values are 'discarded' or that there is 'no disk access', but the main description does not specify side effects, errors, or output behavior.

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 a single, focused sentence that front-loads the action and scope. There is no redundant wording.

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?

The description omits the output format (how labels are returned) and leaves the role of the many optional parameters unexplained. With no output schema and no required parameters, an agent lacks enough context to use the tool confidently.

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 descriptions cover 100% of parameters, so the baseline is met. However, the main description does not clarify which parameter is the main hostname input, and some schema descriptions (e.g., city, zone, query) are unrelated to splitting a hostname.

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 core operation: 'Split a hostname into labels'. It also differentiates from WHOIS/ownership data, but doesn't explicitly identify the 'host' parameter as the primary input.

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 only usage hint is the negative scope 'without WHOIS or ownership data'. It does not name sibling alternatives like normalize-url or browser-url-ok, nor does it specify when this tool should be preferred.

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