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 reveals that a public resource is fetched and only group counts are returned, but it doesn't mention network behavior, error handling, rate limits, or which inputs are ignored—despite the schema showing many params 'discarded after' the call.

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, front-loaded sentence with no filler. It communicates the core action and the sole output detail in six words. This is appropriately concise for the information it carries.

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?

The tool has 9 optional parameters, no output schema, and no annotations, yet the description does not explain which parameter selects the robots.txt URL or what the return structure looks like. An agent cannot reliably invoke this tool correctly from the description alone.

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%, so each parameter is individually documented. The tool description itself adds no mapping between its stated purpose and the 9 parameters, but the schema already provides baseline meaning. An agent still cannot tell which parameter (host, url, or something else) should contain the robots.txt URL.

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 narrows the result scope ('return group counts only'). It is clear about what the tool does, though it doesn't explicitly differentiate it from generic fetch tools like web-fetch or fetch-status.

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 such as web-fetch or domain-shape. There are no explicit when-to-use or exclusions, leaving the agent to infer usage solely from the name and description.

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