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

The description discloses a meaningful non-obvious behavior: page content is not stored. It does not cover other side effects, permissions, or errors, but no annotations are present and the operation appears read-only.

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?

Two short sentences with the main action first and a brief privacy note second; every word carries meaning.

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?

The schema exposes nine optional parameters, several unrelated to URLs, but the description does not clarify that the tool is only for URL host/scheme/status or that other parameters are ignored. With no output schema or annotations, this leaves important context 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?

Schema descriptions cover 100% of parameters, so the baseline applies. The tool description adds no parameter-level meaning, and it leaves ambiguous whether only the url parameter is actually used.

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 states a specific action ('Return') and a precise result ('host, scheme, and HTTP status for a URL'), which clearly distinguishes this from sibling tools focused solely on status, normalization, or content fetching.

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?

The description implies use when host/scheme/status of a URL is needed and hints that page content is not a deliverable, but it does not explicitly say when to prefer this over siblings or name alternatives.

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