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

Beyond the read-only/idempotent annotations, it discloses that the tool fetches and applies RFC 9309 matching, caps extra path testing at five, reports the deciding rule and Content-Signal preferences, and — critically — that each call costs $0.01 via x402 payment. Cost and payment mechanism are behavior an agent must know before invoking and are not captured in annotations.

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?

Two sentences, front-loaded with what is read and what is reported, then the use case, then pricing. The first sentence is long but every clause (crawler list, path cap, deciding rule, Content-Signal) carries real information.

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?

No output schema exists, and the description compensates by stating exactly what is returned per crawler: allow/deny for root plus extra paths, the deciding rule, and Content-Signal preferences. Combined with the disclosed cost, an agent has everything needed to decide and call 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 the baseline is 3; the description earns more by adding the constraint that only up to five extra paths are tested, which the schema does not state (it only caps length at 600 characters). Domain input semantics are left entirely to the schema.

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 ('Reads a domain's robots.txt ... reports ... for each known AI crawler') with concrete scope (site root plus up to five extra paths, deciding rule, Content-Signal preferences). The resource and evaluation standard (RFC 9309) make it clearly distinct from a sibling like llms_txt_check without needing to name it.

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 concrete motivating scenario: 'Use it to see whether a site is open to AI search but closed to AI training.' That tells the agent when the tool's answer matters, but there is no explicit exclusion or mention of when a sibling (e.g. llms_txt_check or geo_audit) would be preferred.

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