Page metadata

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

Strong on economics and mechanics: real-money cost, x402 payment on Base, spending-limit check before charging, and the 10-minute dedupe that returns the earlier result for free (echoed in the schema). It does not explain what happens on failure (refund, partial charge) or how save_to interacts with the paid call, which matters for an irreversible spend; the readOnlyHint=false annotation already signals side effects, so a 3 fits.

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 output shape, then constraints, then cost, then a short usage instruction. The closing "Output: JSON, returned in the tool result" restates what the first sentence already said, a small redundancy in an otherwise tight block.

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?

Since there is no output schema, the description carries the return-shape burden and does so with a field inventory. Missing edge is failure/refund behavior and how save_to/overwrite interact with the charged call, which an agent needs for safe invocation of a paid 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 coverage is 100%, so all five parameters are already documented, and the description mostly repeats that. It does add one real constraint the schema lacks — standard ports and http/https scheme for url — plus the spending context for max_price_usdc, but not enough to lift it above the baseline.

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 concrete verb and resource ("Reads one public web page and returns what it tells search engines and link previews") and enumerates the returned fields (title/description lengths, canonical, redirects, robots rules, OG/Twitter cards, headings, JSON-LD types, SEO issues). That output inventory makes it clearly distinct from siblings like accessibility_check, brand_from_url and image_palette.

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 usable preconditions: one public page, http or https, standard ports, no JavaScript execution, robots.txt respected, and 0.01 USDC per call. It never explicitly names a sibling to use instead (e.g. accessibility_check for audits or brand_from_url for branding), so routing guidance is implied rather than stated.

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