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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states the tool fetches robots.txt and returns group counts, but it does not explain the role of the 9 parameters (many of which are described as 'discarded' in the schema), nor does it mention network requirements, error handling, or what constitutes a 'group count'. The description is minimally transparent about the core action but opaque about the tool's actual behavior.

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 that front-loads the core action and output. There is no fluff or redundant phrasing. However, the extreme brevity comes at the cost of missing critical context, which slightly detracts from the structure score but still earns a 4 for efficiency.

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 annotations, and no output schema, the description is severely incomplete. It does not explain the purpose of the parameters, how to supply the robots.txt URL, what happens to the other inputs, or what the returned group counts look like. An agent cannot reliably call this tool correctly without additional information.

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 description coverage is 100%, the parameter descriptions are generic and unrelated to the tool's stated purpose. For example, 'url' is described as 'HTTPS URL to normalize or cite', which has no apparent connection to robots.txt. The description of the tool does not reference any parameters, so it adds no clarification. The schema descriptions themselves are misleading for a robots.txt inspector, making parameter semantics poor.

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 the exact output ('return group counts only'). This clearly distinguishes it from sibling shape-checking tools like 'domain-shape' or 'github-repo-shape', which target different resources. The tool name aligns perfectly with the stated purpose.

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 gives no guidance on when to use this tool versus alternatives such as 'web-fetch' or 'domain-shape'. It does not mention any exclusions, prerequisites, or conditions that would lead an agent to choose this tool over others. The agent must infer usage from the name alone, which is insufficient.

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