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

With no annotations, the description carries the full burden and goes beyond the basics: it reveals that a live request is sent to verify serving, that unrecognised agents are resolved from robots.txt rather than refused, and that 'refuse' means an allowance is not real. It also links to full verdict definitions. Minor omissions like rate-limit behavior are already covered in the schema.

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 dense but every sentence earns its place: purpose, verdict list, unknown-agent behavior, authoritative link, and audience. It is front-loaded with the core decision purpose. Slightly longer than necessary, but no filler or repetition.

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 description is complete despite having no output schema: it enumerates all possible return verdicts with definitions, explains edge-case behavior for unknown agents, and provides a link for full semantics. Combined with a 100%-covered input schema, an agent has all needed information to invoke the tool 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 coverage is 100%, so baseline is 3. The description adds meaningful context for the 'agent' parameter by explaining it works for any crawler token and how unrecognised agents are handled, which goes beyond the schema's list of examples. It also clarifies the 'domains' parameter's per-domain output semantics.

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?

Description opens with a specific verb+resource ('Decide whether a crawler may fetch a list of domains'), then enumerates the five possible verdicts with precise meanings. It also distinguishes itself from sibling census/site tools by stating it is 'Built for crawler operators rather than site owners' and by handling 'any crawler token, not only the ones this census tracks.'

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?

Explicitly tells when to use the tool ('before spending requests on them') and for whom ('crawler operators rather than site owners'), which excludes site-owner workflows that would be served by other siblings. It also explains the unrecognised-agent behavior, aiding correct selection for non-census crawlers.

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