Accessibility check

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

Beyond the annotations it discloses the real cost and payment rail, that scripts on the page do not execute, that robots.txt is respected, that the result is not a conformance certification, and how duplicate requests within 10 minutes are handled. This is exactly the operational context the 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?

The output shape and caveats are front-loaded, then the cost, then the input instruction, so the most decision-relevant facts come first. It is dense rather than padded, though the payment sentence packs several clauses into one line.

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?

For a paid, single-purpose scanner with no output schema, the description covers what is returned, what is not done, and what it costs. The only real gap is the lack of explicit guidance on when another tool (e.g. page_metadata) is the better choice.

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; the description adds meaning on top by constraining url to a single public page on standard ports and confirming the result is JSON. The other parameters (standard, viewport, save_to, overwrite, allow_repeat, max_price_usdc) are left entirely to the schema.

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 names a specific verb and resource: an automated WCAG check of one public web page, with the engine (axe-core) and the JSON contents spelled out. It is unmistakably different from every sibling in the list, though it never names a sibling to route against.

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 states the input constraint (one public web page, http or https, standard ports) and the payment prerequisite (0.05 USDC on Base via x402 after spending limits are checked). It also sets expectations with 'not a certification of WCAG or ADA conformance', but gives no explicit when-to-use-vs-alternative routing.

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