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

No annotations are provided, so the description carries the full transparency burden. It does add a meaningful non-obvious trait: page content is not stored. However, it does not disclose network behavior, failure modes, rate limits, or whether any requested URL is actually fetched.

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?

The description is two short sentences with no filler. The first sentence states the core action and outputs; the second adds a privacy guarantee. This is appropriately front-loaded and concise.

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?

Given no annotations, no output schema, nine optional parameters, and a large sibling set, the description is incomplete. It does not explain the response format, how to handle the unrelated optional parameters, or when to prefer this tool over nearby siblings. The one-sentence status and privacy note only partially compensates.

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 description coverage is 100%, so all nine parameters already have documentation. The tool description adds little beyond identifying 'URL' as the core input; it does not clarify how the other optional parameters relate to the host/scheme/status output. Baseline 3 applies because the schema handles parameter explanation.

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 uses a specific verb ('Return') and names exact outputs (host, scheme, HTTP status) for a URL, making the tool's purpose immediately clear. It also implicitly distinguishes itself from siblings like web-fetch by adding 'Page content is not stored.'

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 gives no explicit when-to-use guidance, alternative tool names, or exclusion criteria. The privacy note is a behavioral hint, not enough for an agent to decide between this and similar URL tools like fetch-status, normalize-url, or web-fetch.

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