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

The description adds 'public' (suggesting unauthenticated access) and 'group counts only' (output limitation), which are genuinely useful beyond the readOnlyHint and destructiveHint annotations. It does not cover failure modes or edge cases, but it adds meaningful behavioral scope.

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?

One sentence, front-loaded with the action, and no wasted words. The key restriction ('group counts only') is included without elaboration.

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 is simple, but the complete absence of parameter mapping makes it incomplete for safe invocation. The description also omits error behavior for robots.txt absence or invalid URLs, and with no output schema the agent is left guessing at the exact return shape.

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 describes all seven parameters generically, but the description never says which parameter should contain the robots.txt location. An agent cannot reliably choose between 'url', 'host', or 'path', so the description fails to bridge the tool-level purpose to the actual parameters.

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 return only group counts. The 'only' qualifier sharply distinguishes this from sibling tools like web-fetch or fetch-status, making the tool's scope immediately clear.

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?

The description implies the tool is for cases where robots.txt group counts are enough, rather than full content, but it never names alternatives or states when not to use it. Usage context is inferable, not explicit.

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