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

No annotations are provided, so the description must carry the full burden of behavioral disclosure. It only mentions that WHOIS/ownership data is excluded, but does not explain how the tool handles the nine parameters, whether it makes network calls, or what side effects occur. For a tool with this many parameters, this is a significant transparency gap.

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 sentence that front-loads the main action and avoids unnecessary words. It is efficient and to the point, though its brevity contributes to the lack of context. As a concise statement, it earns a 4.

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?

With nine optional parameters and no output schema, the description is far too sparse. It does not explain the purpose of the unrelated parameters, how they relate to hostname splitting, or what the tool returns. The description is incomplete for an agent to call the tool correctly without additional assumptions.

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% and each parameter has a detailed description (e.g., 'Git ref name; discarded after the shape check'), so the baseline is 3. However, the tool description itself adds no parameter information and does not even indicate which parameter corresponds to the 'hostname' mentioned. The narrow description clashes with the broad schema, confusing which parameters are relevant to the stated purpose.

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') and differentiates from sibling shape tools by specifying hostname. However, the input schema includes nine parameters, many of which (city, json, path, zone, query) are unrelated to hostnames, creating ambiguity about the tool's actual scope. The narrow description conflicts with the broad parameter list, reducing clarity.

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?

The description provides no guidance on when to use this tool versus alternatives. It does not mention any prerequisites, exclusions, or context for choosing it over similar shape tools. A single sentence with no usage conditions leaves the agent without direction.

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