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

No annotations are provided, and the description does not disclose any behavioral details such as side effects, permissions, or whether the operation is read-only. The phrase 'without WHOIS or data' is too vague to serve as a transparency statement.

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 concise but poorly structured. The phrase 'without WHOIS or data' is confusing and detracts from the otherwise simple statement. It could be clearer if the irrelevant clause were removed or rephrased.

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?

With no output schema, no mention of return values, and a set of seemingly unrelated parameters, the tool lacks the contextual information needed to understand its intended behavior or how to invoke it correctly. The description does not fill these gaps.

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 the schema has 100% coverage, the descriptions are largely irrelevant to the stated purpose. Parameters like 'city', 'zone', and 'query' have no obvious connection to splitting a hostname, while 'host' or 'url' are the only plausible inputs. The descriptions do not clarify how the tool uses them or which are required for the core action.

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 the primary verb and object ('Split a hostname into labels'), but the trailing phrase 'without WHOIS or data' is ambiguous and does not clarify the tool's scope. It does not distinguish this tool from siblings that also deal with URLs or hostnames, such as normalize-url or figma-url-shape.

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 guidance is given on when to use this tool instead of alternatives. There is no mention of conditions, prerequisites, or typical use cases, leaving the agent without any decision support.

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