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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world). The description adds substantive domain context beyond that: it separates operator-documented tokens from widely-written tokens no operator sends, and explains that the latter make a robots rule unenforceable. It stops short of describing output format or ordering.

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 primary return content is front-loaded in the opening clause, followed by the supporting categories and then a brief usage note. Despite the dense parenthetical, every clause carries information and nothing is redundant.

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?

With no parameters and no output schema, the description must carry the burden of explaining what comes back, and it does: it names the token categories and the verdict-name list. An agent knows what to expect without a schema.

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 tool takes zero parameters, so there is nothing to document and the baseline of 4 applies. The description correctly spends no space on parameter semantics and instead describes the returned content.

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?

Names a specific verb (returns) and resource (the AI crawler tokens this index reads robots.txt rules for), and enumerates the three categories of content returned. It does not explicitly contrast itself with access_check_url or access_explain_verdicts, though the scope is clear enough to distinguish it in practice.

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 an explicit use context — 'Useful when writing or auditing a robots.txt' — which tells the agent when this tool is relevant. It does not state when NOT to use it or name an alternative sibling, so it falls short of the top band.

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