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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It only states the core transformation and one negative ('without WHOIS or ownership data'), without mentioning return format, side effects, discarded inputs, or error 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 active sentence with no filler, and the main limitation is woven into the first clause. It is appropriately sized and front-loaded.

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?

Despite the concise sentence, the tool has 9 optional parameters and no output schema or annotations, so an agent cannot tell which parameter to pass or what the tool will return. The description does not compensate for that gap, making it incomplete for reliable invocation.

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 coverage is 100%, so the baseline is met without extra parameter explanation. However, the description adds no parameter-level guidance beyond implying that 'host' is relevant, and the schema contains eight unrelated optional parameters that could confuse an agent.

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 specific action ('split'), a specific resource ('hostname'), and a clear output ('labels'). It also explicitly excludes WHOIS/ownership data, which helps distinguish it from enrichment or domain-information tools among the siblings.

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?

There is no explicit 'use when' or named alternative, but the wording implies the tool is for hostname splitting/shape tasks and not for WHOIS/ownership lookups. This is minimal implied usage guidance; it does not direct the agent away from sibling shape/validation tools.

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