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

Annotations only declare the generic read-only/idempotent/open-world profile, yet the description discloses the paid x402 v2 flow in detail: cost per call, the PaymentRequired error shape, the exact retry path via params._meta['x402/payment'], and the rule that invalid or fully failed calls are never charged. It also adds robots.txt compliance, the User-Agent used, and private-address refusal — behavioral traits no annotation conveys.

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?

Single dense block that is front-loaded with the purpose and return shape before moving to constraints and payment mechanics; every sentence carries information. It is long, but the density is warranted rather than padded.

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 carries the return-value burden and does so fully (Markdown body plus title, description, language, canonical URL, word count), while also covering size limits, bot-wall limits, and payment failure semantics. Nothing an agent needs 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?

Schema coverage is 100%, so the baseline is 3, but the description meaningfully extends both params: the 3-URL paid cap and the payment retry contract for x402_payment (base64 signed payload, PAYMENT-SIGNATURE header, never a private key) supply operational context beyond the schema text.

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 ('Read web pages... returns each page's main content as clean Markdown') and enumerates exactly what is stripped (navigation, scripts, ads) and what is kept. This clearly distinguishes it from the sibling document_to_markdown, which handles files rather than live URLs.

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 strong when-not guidance ('Does not get past bot walls', refuses private/internal addresses) and lays out the paid-tier condition and charge policy. It never names a sibling alternative such as document_to_markdown or url_status_check, so the agent must infer routing, but usable context is clearly present.

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