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

The description does not disclose that most inputs are discarded (only a 'shape check' is performed) or that no side effects occur. While individual parameter descriptions in the schema mention discarding, the tool-level description fails to convey the overall behavioral contract.

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 very concise, consisting of a single unambiguous sentence with no redundant wording. However, it lacks any structured breakdown (e.g., sections or bullet points) that might help clarify its relationship to the schema.

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 complexity of the schema (9 parameters, all optional) and the presence of many related shape-checking siblings, the description is severely incomplete. It does not explain the shape-checking behavior, the role of non-host parameters, or how results are returned, leaving the agent without essential context.

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?

The description does not clarify why there are nine parameters or which one (e.g., 'host') is central. It adds no explanation of how the parameters relate to the hostname-splitting purpose, leaving the schema's listed parameters—many marked as discarded—without contextual 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 names a specific action ('split a hostname into labels') and clarifies a boundary ('without WHOIS or ownership data'), but it does not mention the 'shape' validation role implied by the tool's name and sibling tools, making the intended purpose ambiguous.

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 provided about when to use this tool versus the many sibling shape-checking tools (e.g., figma-url-shape, wiki-title-ok), and there is no mention of what inputs are valid or how the tool should be invoked.

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