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

With no annotations, the description carries the full behavioral burden and does well on the critical detail: it discloses that the call is paid via x402, charged only on success, and that unpaid calls return payment requirements requiring a retry with _meta["x402/payment"]. It does not describe rate limits or other failure modes, but the payment behavior is unusually well covered.

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 front-loaded with the returned fields and follows with necessary payment mechanics. Every sentence carries useful information, with no repetition or 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?

There is no output schema, but the description lists the metadata categories an agent will receive and explains payment/retry behavior. It is largely complete for a one-parameter extraction tool, though it could say more about return structure and sibling differentiation.

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 description coverage is 100% and the single url parameter is already documented as a public http(s) HTML page. The description does not add syntax or format details beyond the schema, so the baseline 3 is appropriate.

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 enumerates the exact metadata fields returned (title, meta description, canonical, lang, OpenGraph/Twitter tags, JSON-LD), so the resource and output scope are clear. It does not explicitly distinguish this from the scrape or scrape_lite siblings, which keeps it from a 5.

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 invocation guidance around payment and retry behavior, but does not state when to choose this tool over scrape, scrape_lite, or map. Usage is implied by the metadata-specific output list rather than explicitly contrasted with alternatives.

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