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

With no annotations and a terse description, there is no indication of side effects, data access, or safety profile. The mention of 'discarded after the shape check' hints at ephemeral handling but is too vague to be informative.

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 brief but not well-structured. The single sentence mixes a functional statement with a negative qualifier, and the parameter descriptions are formulaic, adding length without clarity.

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's complexity (9 optional parameters, no output schema), the description is severely incomplete. It does not explain what 'shape check' means, what the expected output is, how parameters are used, or any return format, 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?

Although each parameter has a description, the descriptions are generic, misleading, or unrelated to the purported hostname-splitting functionality. For example, 'ref' is labeled as a 'Git ref name' and 'city' as a 'City name for a public weather hint', which do not align with the tool's stated purpose, providing no meaningful semantics.

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 hostname into labels') but the parameter list contains many unrelated fields, making the tool's actual purpose ambiguous. The phrase 'without WHOIS or ownership data' adds confusion rather than clarification.

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 on when to use this tool versus sibling tools like normalize-url or browser-url-ok. The description offers no context for selection or exclusion.

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