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

With no annotations, the description must carry behavioral disclosure. It only states that WHOIS/ownership data is not included; it does not mention whether network access occurs, how output is formatted, what happens on invalid input, or whether any state is changed.

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 and is front-loaded with the main action. It loses some structure by adding an unfocused negative qualifier, but it is not bloated.

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 tool has nine optional parameters, no output schema, and no annotations, yet the description does not identify the required input, expected output, error behavior, or relationship to sibling tools. This is too incomplete for an agent to invoke reliably.

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?

Although schema description coverage is 100%, most parameter descriptions are unrelated to splitting a hostname (e.g., 'City name for a public weather hint', 'JSON text to validate') and do not clarify which field should be used. The description adds no cross-parameter meaning.

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 clear verb and resource ('Split a hostname into labels'), but the qualifier 'without WHOIS or ownership data' is ambiguous and the input schema includes many unrelated optional fields (city, feed, json, path, zone, query), so the actual purpose is not confidently distinguishable.

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?

No explicit when-to-use guidance is given, and there is no comparison to sibling tools such as public-suffix or normalize-url. The phrase 'without WHOIS or ownership data' is the only usage hint, which is not sufficient to route an agent correctly.

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