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

The description discloses that only group counts are returned, which is useful. However, it does not mention that most of the 9 input parameters are discarded (as stated in the schema) or that the tool makes a network request, nor does it clarify that only the 'url' parameter is actually used. With no annotations, this lack of clarity about the tool's real behavior is a significant 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 with no fluff, which is concise and front-loaded with the core action. However, it is so terse that it omits critical invocation details, but that is more a completeness issue than a conciseness issue. The structure is efficient.

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?

Given the tool has 9 optional parameters, no output schema, and no annotations, the description is severely incomplete. It does not explain the purpose of the many seemingly unrelated parameters, does not indicate which parameter is the robots.txt URL, and does not describe the format of the group counts returned. An agent would struggle to call this tool 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?

Schema description coverage is 100%, so each parameter already has a clear description (e.g., 'Git ref name; discarded after the shape check'). The tool description adds no additional parameter information, which is acceptable given the schema's completeness. Baseline of 3 applies because the schema carries the burden.

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 action ('Fetch a public robots.txt') and result ('return group counts only'), which is clear. However, it does not specify which input parameter provides the robots.txt URL, and the parameter list contains many unrelated fields (city, zone, query, etc.) that appear irrelevant to the described purpose, creating ambiguity about how to actually invoke the tool.

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 guidance on when to use this tool versus the numerous sibling tools (e.g., web-fetch, fetch-status, browser-url-ok). No exclusions, alternatives, or prerequisites are mentioned, leaving an agent without context to choose it correctly.

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