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

No annotations are provided, so the description carries full responsibility. It mentions a behavioral constraint ('without WHOIS or ownership data') but fails to disclose side effects, error handling, return format, or network access. The schema notes that some parameters are 'discarded after the check,' but that is not in the description. The description is too sparse to inform safe invocation.

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 filler. It is efficient in communicating the core action. However, its brevity borders on under-specification, omitting essential usage and behavioral details, so it earns a high but not perfect score.

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 parameters, no annotations, and no output schema, the description is severely incomplete. It does not explain the purpose of the extra parameters, return values, error behavior, or edge cases. An agent has little guidance beyond the schema, which itself is confusing given the tool's stated purpose. The description is inadequate for safe and correct usage.

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 schema coverage is 100%, the description adds no value about the parameters. It does not clarify which parameter (e.g., 'host') is the hostname to split, nor does it explain the role of the other eight parameters (city, feed, json, etc.) in relation to the stated purpose. This disconnect makes the description misleading and fails to compensate for the parameter diversity.

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 clear verb ('split') and resource ('hostname'), and adds a distinguishing negative ('without WHOIS or ownership data') that separates it from siblings like fetch-status or normalize-url. However, it is terse and does not reconcile with the nine heterogeneous parameters in the schema, so it could mislead an agent about the tool's actual scope.

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 guidance on when to use this tool versus alternatives. The only hint is the negative 'without WHOIS or ownership data,' which implies a limitation but does not state conditions for selection or mention any prerequisite or context. An agent would have to infer usage from the name and schema.

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