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

With no annotations provided, the description carries the full burden of disclosing side effects and data handling. It only states what the tool does not do (WHOIS/ownership lookup) and gives no indication of read-only behavior, persistence, or potential side effects. Some parameter descriptions mention 'discarded,' but the main description itself lacks behavioral transparency.

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, compact sentence with no fluff and puts the main action first. It is concise and easy to parse, though it omits any structured detail about inputs or outputs, which slightly limits its usefulness.

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?

Given the tool has nine parameters and no output schema or annotations, the description is too thin to be complete. It does not explain which parameters are required, what the return value looks like, how to handle the apparently unrelated parameters, or how this tool fits among the many 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?

All nine parameters have schema descriptions, giving 100% coverage, and the 'host' parameter aligns with the tool's stated purpose. However, the description itself does not clarify the roles of the many other parameters, several of which appear unrelated (e.g., 'city,' 'feed,' 'json'), leaving their relevance to 'domain-shape' unclear.

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 primary action—splitting a hostname into labels—and adds a useful boundary by noting it does not involve WHOIS or ownership data. However, it does not explicitly identify which input parameter (likely 'host') is used, leaving some ambiguity.

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 offers no explicit guidance on when to choose this tool over alternatives, aside from a vague negative clause about WHOIS/ownership data. It does not mention related sibling tools or typical use cases, so an agent has little basis for deciding when to invoke it.

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