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

With no annotations, the description carries the full burden, but it only discloses that the resource is public and that output is limited to group counts. It does not cover error behavior, what the 'group counts' look like, or which parameters are used/discarded.

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 no filler. It is concise, though it omits important invocation details that other dimensions penalize.

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 9 parameters, no output schema, and no annotations, this brief description is not complete enough. It fails to say which parameter selects the robots.txt source, what a successful result contains, or how failures are surfaced.

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 coverage is 100%, so the baseline is 3 even though the description adds no parameter mapping. However, the schema descriptions are generic (e.g., 'HTTPS URL to normalize or cite') and do not clearly identify which parameter is the robots.txt URL, so the description misses a chance to resolve that ambiguity.

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 clear action ('Fetch a public robots.txt') and a specific output ('return group counts only'), so an agent understands the core purpose. It does not explicitly name sibling tools, but the robots.txt focus is distinct enough from web-fetch/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 about when to use this tool versus siblings like web-fetch, fetch-status, or normalize-url, and no alternatives or exclusions are mentioned. The only implied use case is needing robots.txt group counts.

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