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 a negative constraint—no WHOIS/ownership data—and gives no information about side effects, return format, error behavior, or whether the input is transformed or discarded. For an unannotated tool, this is insufficient.

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, front-loaded sentence with no wasted words. It states the core operation and an important limitation efficiently. It is concise, though slightly too terse to cover the tool's actual complexity.

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 and no output schema, yet the description only covers the hostname scenario. It does not explain what the tool returns, why other parameters exist, or how to choose among them. This leaves significant context missing for an agent deciding whether and how to invoke the tool.

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 description coverage is 100%, so the schema already documents each parameter. The description adds only a hint that 'hostname' relates to the host parameter, but it does not explain the nine-parameter superset or add format-level detail beyond the schema. This matches the baseline for high schema coverage.

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 verb and resource: split a hostname into labels. It also adds a meaningful delimitation—'without WHOIS or ownership data'—which distinguishes it from ownership-oriented tools. However, it does not mention the broader 'shape' validation nature of the tool or the fact that the input schema contains many unrelated parameters.

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 guidance is given for when to use this tool versus alternatives. The phrase 'without WHOIS or ownership data' implies it is not for ownership lookups, but no sibling tool or contrasting use case is named. An agent is left to infer when this tool is the right choice.

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