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

With no annotations, the description must disclose behavior itself. It says it fetches and returns group counts, but it does not explain that many parameters are discarded, what happens on fetch failure, or whether it actually validates robots.txt syntax. The schema shows that most parameters are 'discarded after the shape check,' but the description omits this entirely, which is a significant transparency 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, front-loaded sentence with zero filler. It is appropriately concise for a simple fetch-and-count operation.

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?

Despite having 9 parameters, no output schema, and no annotations, the description is far too minimal. It does not indicate which parameter to use, what the output format looks like, or any error handling. An agent cannot reliably call this tool without additional knowledge.

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 schema has 100% coverage, but the descriptions are unrelated to robots.txt (e.g., 'City name for a public weather hint', 'Git ref name'). The tool description does not clarify which parameter is the robots.txt URL; it merely repeats the action. It fails to resolve the ambiguity introduced by the schema, so it adds no value beyond the structured fields.

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 is specific: 'Fetch a public robots.txt and return group counts only.' It clearly names the resource (public robots.txt) and the output (group counts). It distinguishes this tool from siblings that deal with URLs, statuses, or other shapes.

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 on when to use this tool vs alternatives. There is no mention of when to prefer it over web-fetch or fetch-status, nor any exclusions or conditions. The description only states what it does, leaving 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.