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

With no annotations, the description carries the full burden. 'Return group counts only' is a useful behavioral limitation, but the description does not disclose safety, side effects, error handling, or what happens with invalid URLs.

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, front-loaded sentence with zero unnecessary words. It is appropriately concise and immediately states the core action and output.

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 description is too minimal for a tool with nine parameters and no output schema. It fails to map the core action to any specific parameter and gives no return format beyond 'group counts', leaving the agent to infer which of the many inputs is relevant.

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?

The input schema describes all nine parameters with reasonable detail, so the description adds no extra meaning. It does not indicate which parameter is the primary input for the robots.txt URL, but the schema's coverage is sufficient to warrant the baseline score.

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 clearly states a specific verb and resource: fetch a public robots.txt and return group counts only. It is clear about what the tool does, but it does not explicitly differentiate it from siblings 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?

There is no guidance on when to use this tool versus alternatives. The description implies usage through the name and behavior but provides no explicit context, exclusions, or alternative references.

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