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

No annotations are provided, so the description bears the full burden. It only states an action and a negative scope ('without WHOIS or ownership data'), but provides no information about side effects, read-only nature, rate limits, or other behavioral traits.

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, concise sentence that directly states the tool's purpose without unnecessary words or filler.

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 is severely underspecified for a tool with four optional parameters and no output schema. It does not describe the output format, error conditions, or the purpose of unrelated parameters, leaving an agent without enough context to use the tool correctly.

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?

The schema already has descriptions for all four parameters (100% coverage), so the baseline of 3 applies. The tool description does not meaningfully clarify how the parameters relate to the operation; for instance, it does not explain why 'json' and 'zone' are present when the tool is about 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 a specific action (split a hostname into labels) and resource (hostname). However, it does not differentiate this from sibling tools like normalize-url or validate-json, which could also involve parsing or processing URLs/hostnames.

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 minimal implied usage (pass a hostname) but does not explain when to choose this tool over siblings, nor does it clarify which of the four parameters (url, host, json, zone) are relevant or required. No exclusions or alternative tools are mentioned.

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