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

With no annotations, the description carries the full behavioral burden. It does disclose a meaningful trait beyond the schema: the $0.005 USD / x402 cost, which tells the agent each call is paid. However, it says nothing about rate limits, whether dynamic pages are rendered, robots.txt/ToS handling, or failure behavior when no contact info exists.

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?

One sentence, fully front-loaded with the core capability, with the pricing detail tucked into a parenthetical at the end. No filler and nothing redundant.

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 one-parameter extraction tool with no annotations and no output schema, the enumerated output types partially substitute for a return-value spec. Still missing is any usage context and behavioral detail (auth, limits, absence-of-results handling), leaving clear gaps.

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 a single parameter with 100% schema description coverage ('Target website URL or domain name'), so the schema already documents it fully. The description adds no additional meaning about the URL parameter, 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 gives a specific verb ('Extracts') plus the exact resource types returned: emails, phone numbers, social profiles, and contact page links. This enumeration distinguishes it well from generic siblings like extract_website_metadata, but no sibling is named explicitly, so it stops short of a 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 guidance on when to choose this tool over alternatives such as extract_website_metadata, nor any prerequisites, page-selection rules, or exclusions. The agent must infer usage entirely from the tool name.

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