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

Goes well beyond the annotations (readOnlyHint/openWorldHint/idempotentHint) with genuinely useful behavioral context an agent cannot infer: it respects robots.txt, it is not charged when the page is not a product page, it reports which extraction method was used, and it costs $0.01 USDC via x402 or prepaid credits. Billing behavior and the non-charge condition are exactly the kind of disclosure annotations do not carry.

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?

Front-loads the core capability and then layers method fallback, compliance, and billing. Dense but nearly every clause carries information. The parenthetical asides ($0.01, x402/prepaid) make it slightly cluttered, keeping it short of a 5.

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?

An output schema exists, so return values need not be explained. For a single-param tool the description covers the two-path extraction logic, the disclosure of which path was used, robots.txt compliance, the non-charge edge case, and cost. Nothing an agent needs to call it 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 description coverage is 100% and the single `url` parameter is already documented as 'A product page address.' The description adds only the qualifier 'any public product page', which is marginally more than the schema but not meaningful syntax or format detail. 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?

States a specific verb and resource set: extracts name, brand, price, currency, availability and SKU from any public product page, and explains the two extraction paths (schema.org/OpenGraph vs AI page reading). An agent immediately understands what comes back. However, it never distinguishes itself from the sibling tool `product`, which appears to cover the same resource, so the 'distinguishes from siblings' bar for a 5 is not met.

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?

Implies context ('any public product page, even without structured data') but never states when to pick this over the `product` sibling, `extract`, or `extract-json`. No explicit when-not guidance either. The pricing note hints at cost tradeoffs but doesn't route the agent to a cheaper alternative.

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