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

With no annotations provided, the description must carry the full burden of behavioral disclosure. It implies a network fetch but does not state that the operation is read-only, that most parameters are ignored, or that the result is limited to a count. The schema notes that parameters are 'discarded after the shape check', but the description itself adds no such context.

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 concise sentence with no fluff, but it is under-specified rather than efficiently informative. It is too brief to convey the necessary context for a tool with 9 parameters and no output 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?

This tool has 9 parameters, no output schema, and no annotations. The one-sentence description is completely inadequate to explain which parameter to use, what 'group counts' means, or how the tool behaves. An agent cannot reliably determine how to invoke 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?

Although the schema provides 100% coverage with descriptions for all 9 parameters, the tool description does not clarify which parameter holds the robots.txt URL. The 'url' parameter is described as 'HTTPS URL to normalize or cite', not as the target of the fetch, so the mapping between the description and the schema is ambiguous. The description adds no extra meaning beyond the schema.

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 ('Fetch a public robots.txt') and a specific output ('return group counts only'), so the core purpose is identifiable. However, it does not distinguish this from sibling tools like web-fetch or fetch-status, and the 9 unrelated parameters (ref, city, json, etc.) make it unclear how the purpose maps to the inputs, lowering 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?

No guidance is given on when to use this tool versus alternatives. It does not mention that it is a shape-check or validation tool, nor does it suggest using it specifically for robots.txt inspection over other fetch tools. The absence of any contextual or alternative references leaves usage entirely to inference.

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