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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint, so the safety profile is covered; the description adds the non-obvious commercial and execution behaviour instead. It discloses the exact price (0.08 USDC), the payment mechanism (x402 automatic), the failure-charge policy ('never charged if the call fails'), and that all checks derive from one page read.

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?

It is front-loaded with what the call returns before moving to audience and pricing, and every sentence carries information. The audience-targeting sentence ('agency audits, lead qualification, prospect research') is mildly promotional but still aids selection.

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 compensates by enumerating the five check categories the caller will receive, and it fully covers cost and payment preconditions. It does not describe the shape of the returned payload or any rate limits, which is the remaining gap for a paid aggregate tool.

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% for both parameters (url and optional keyword with its 120-char limit), so the schema does the documentation work. The description adds no syntax, format or default detail beyond what the schema already states, making the baseline 3 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 states a specific verb and resource plus an enumerable scope: it aggregates the landing page audit, business contact details, tracking/pixel check, structured data check and crawlability check in a single call. This makes it trivially distinguishable from each of the sibling tools, which perform those checks individually.

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 clear context for choosing it ('ideal for agency audits, lead qualification and prospect research') and an economic rationale for preferring it over the individual siblings ('for less than the tools cost separately'). It stops short of an explicit when-not-to-use rule (e.g. 'use the individual check tools if you only need one signal'), so it is clear but not exhaustive.

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