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

Goes well beyond the readOnly/openWorld/idempotent annotations: it discloses the x402 payment handshake (first call returns payment terms, then retry with _meta["x402/payment"]), the $0.10 price, and the ~5-15 s runtime. It also enumerates exactly what gets checked (404s, mixed content, headings, structured data, OG, robots.txt/sitemap/llms.txt) and how issues are ranked.

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 non-obvious payment mechanics, then scope, deliverables, runtime, and the upsell. The long list of checked items is dense but each item earns its place; the only mildly redundant bit is restating the LITE-vs-$2 framing twice.

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, and the description compensates by enumerating the returned issues and inspected surfaces, plus the price, runtime, and payment flow an agent needs before calling a paid open-world tool. Nothing material for correct invocation 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?

There is only one parameter and schema description coverage is 100%, so the schema already defines 'url' as a public http(s) URL or bare domain. The description adds no format or edge-case guidance beyond that, 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+resource+scope: a LITE one-page SEO audit returning the top 10 issues ranked by severity and effort. It explicitly distinguishes itself from the full $2 SEO Audit tier, but says nothing about how it differs from sibling tools like seo_page or page_quality that also analyze a single page.

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?

"LITE version of the $2 SEO Audit: one page" plus the explicit upgrade line gives a clear cost/scope tradeoff for choosing this over the full audit. It stops short of naming when to prefer sibling single-page tools (seo_page, page_quality, page_meta) instead.

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