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

Annotations only declare readOnlyHint and openWorldHint, so the description carries real added burden and delivers: the static-HTML limitation (JS-injected scripts invisible), the privacy handling (cookie names/flags, never values), and the full cost model — $0.002 USDC via x402 on Base/Solana/Arc, with failed calls uncharged. That cost and failure-billing detail is exactly what an agent needs before invoking.

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 sentences, front-loaded with the returned payload, then the static-HTML caveat, then pricing — a sensible priority order. The parenthetical category and payment-rail lists make the middle dense, but each clause carries distinct information rather than filler.

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?

For a one-parameter, read-only extraction tool with an output schema, the description still covers scope limitation, privacy behavior, and billing. Nothing an agent needs in order to call this correctly is missing.

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?

Only one parameter (url) with 100% schema description coverage, so the schema already does the work. The description's 'Static HTML only' phrasing implicitly constrains what the URL should point to, but adds no syntax or format detail beyond the schema's 'Page address, https://…'.

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 resource (third-party script and iframe hosts on a page) and enumerates exactly what is returned: per-host classification across named categories, the cookies the first response sets (names and flags only), and consent-manager presence. An agent can distinguish this from siblings like headers, robots, meta, or links without opening any schema.

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?

The description gives a meaningful scope constraint ('Static HTML only: scripts added at run time are not seen') that tells the agent when results will be incomplete, but it never names an alternative sibling or states an explicit when-to-use trigger. Usage is implied rather than directed.

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