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

No annotations are provided, so the description carries the full disclosure burden. It usefully surfaces a behavioral trait structured fields cannot express — the $0.002 USD / x402 cost — but says nothing about read-only semantics, rate limits, partial-failure behavior for unreachable URLs, or response shape. Cost disclosure is real added value, so this is above a bare 2 but well short of complete.

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?

A single front-loaded sentence: verb first, the full field inventory next, cost in parentheses at the end. No filler, no restatement of the tool name, and every element earns its place.

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 enumerated field list (title, meta description, OpenGraph, Twitter Cards, canonical URL, JSON-LD, headings) effectively stands in for a return-value spec, which is exactly what the agent needs for this simple one-param tool. What is missing is failure behavior on invalid or unreachable URLs, which keeps it from a 5.

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?

Only one parameter exists and schema description coverage is 100%, so the schema already documents 'url' as 'Target webpage URL or domain name.' The description adds no format, normalization, or edge-case detail (e.g., how a bare domain is handled versus a full URL), 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 ('Extracts') plus the exact set of resources returned (title, meta description, OpenGraph, Twitter Cards, canonical URL, JSON-LD, headings), which is far more concrete than a generic 'get metadata' phrasing. It does not, however, distinguish itself from overlapping siblings such as run_full_seo_audit or run_spider_view_scan, so it lands at 4 rather than 5.

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?

There is no when-to-use guidance, no mention of prerequisites, and no routing to or away from alternatives, even though siblings like run_full_seo_audit and run_spider_view_scan plausibly overlap. The agent must infer usage purely from the purpose text.

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