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

Annotations already declare readOnly/idempotent/openWorld/non-destructive, and the description goes well beyond that by disclosing the evaluation algorithm (most specific user-agent group, longest matching rule, Allow wins ties, * and $ wildcards) and the nature of the result (allowed/blocked per crawler plus the deciding rule). The optional override of the live file is also made explicit.

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?

Three dense sentences, front-loaded with the core action, then the matching rules, then the optional override. No redundant or filler text.

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?

An output schema exists, so return values needn't be specified; annotations cover the safety profile; and the description covers the evaluation semantics and the live-vs-proposed mode. An agent has everything needed to call this 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 the schema already documents url, robots_txt and user_agents (including the default crawler set). The description restates the live-vs-proposed distinction but adds no syntax, format or constraint detail beyond what the schema provides.

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?

States a specific verb and resource ('Test a URL against the site's live robots.txt') and quantifies scope ('one or more crawlers'), plus the exact matching semantics used. This is clearly distinguishable from siblings like ai_crawler_policy or check_ai_visibility, which concern policy/visibility rather than robots.txt rule evaluation.

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?

Gives a clear use context: evaluate a URL against the live file, or against a proposed robots.txt instead of the live one. It does not, however, name an alternative tool or state when-not to use this one (e.g., versus the ai_crawler_policy sibling), so routing is left partly to inference.

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