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

Annotations already cover the safety profile (readOnly, openWorld, idempotent), and the description layers on genuinely new operational facts: a 0.05 USDC cost per completed call, automatic x402 payment, and — critically — that failed calls are never charged. That cost/charging behavior is exactly the kind of trait structured fields cannot express.

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-loaded with purpose and return shape, then pricing. The middle enumeration of return values is long but each item is informative. No filler sentences, though the output list could be tightened.

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 correctly carries the return contract (0-100 score, verdict values, tag detection, conversion paths, top 5 fixes), so an agent knows what it gets. It also covers cost and refund behavior. Minor gaps remain around latency/pagination, but the essential contract is present.

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 both parameters (url, keyword) are already documented in the schema. The description adds no syntax, format, or interpretation detail for either parameter, so the 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?

States a specific verb and resource ("Audit a landing page") plus a concrete scope ("before sending paid ad traffic"). It does not name or distinguish itself from the close siblings preview_landing_page or sample_audit, so an agent must infer the difference.

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 a clear usage trigger — run it before spending on paid traffic — which tells the agent when this tool is relevant. It offers no exclusions or explicit routing to alternatives such as preview_landing_page or sample_audit, which would be valuable given the sibling set.

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