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

No annotations are provided, so the description carries full disclosure burden. It enumerates returned data (HTTP status, Last-Modified/ETag, SHA-256 fingerprint, changed flag), explains unsigned/rate-limited free tier versus paid signed attestation, and details payment headers/transport options. This is strong behavioral transparency for a read-only verification call.

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 purposeful, front-loading the tool's purpose before payment/auth details. The pricing and header information is somewhat lengthy, but every sentence conveys necessary operational information, so it earns a 4 rather than a lower score.

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 output schema, the description compensates by itemizing return values and the signed/unsigned distinction. It also covers rate limits, payment header variants, pricing, and cross-transport equivalence. The only minor omission is a numeric rate limit, but the overall guidance is complete enough for correct invocation.

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%: url and prior_hash each have descriptions in the schema. The description adds context by explaining that prior_hash enables change detection, but it does not materially extend the schema semantics, so baseline 3 applies.

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 opens with a concrete question, 'Is this URL live, and has this page changed?', then states a specific check: uptime, content fingerprint, and change detection. This clearly distinguishes it from sibling verify_business/verify_claim/verify_price tools, which are domain-specific verifications.

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?

It gives explicit usage contexts: 'before your agent acts on its contents, to detect stale data, or to decide whether to invalidate a cache.' It does not explicitly name sibling alternatives or say when not to use it, but the domain of freshness is apparent and the context is clear.

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