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

With no annotations, the description carries full burden. It clarifies that WHOIS/ownership data is not retrieved, but omits that the tool performs shape checks (per schema) and discards inputs, and does not disclose return behavior or side effects for the many parameters.

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 one short sentence, which is concise, but it is inaccurate and incomplete. It does not earn its place because it misrepresents the tool's scope, so brevity is not a virtue here.

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?

For a tool with 9 optional parameters, no required parameters, and no output schema, the description is woefully insufficient. It does not explain how the tool processes each parameter, what it returns, or when it is appropriate, leaving an agent unable to call it correctly.

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 3, but the description adds no meaning for parameters—it only mentions hostname splitting while the schema includes a 'host' parameter plus many others. The description fails to connect itself to the actual parameters, and may mislead an agent into thinking only hostname input is valid.

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 claims a specific action (split hostname into labels) but the schema exposes 9 unrelated parameters (ref, url, city, feed, json, path, zone, query) that are discarded after shape checks. It does not describe the actual multi-purpose validation behavior, making the purpose vague and partially misleading.

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 versus siblings like figma-url-shape or github-repo-shape. The description does not state conditions, exclusions, or alternatives.

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