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

With no annotations available, the description carries the full burden. It does disclose the HTTP method (HEAD) and that only status is returned, which implies a lightweight, read-only operation. However, it never mentions timeouts, redirects, auth requirements, or that only the URL parameter is used—behaviors that would matter for an HTTP network call.

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 action sentence with zero fluff. Every word earns its place; the description is compact and immediately readable.

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 description mentions only HEAD-ing a URL, yet the schema lists 9 different parameters (city, json, zone, etc.) with hints that they are validation-only. It is unclear how these parameters relate to the HEAD action or whether other parameters can drive the tool. The description is too sparse for the complexity implied by the schema.

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%, and the tool-level description adds no parameter-specific meaning. All parameters are well-documented in the schema, so the description does not need to compensate; 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?

The description states a clear action—'HEAD a public URL'—and explicitly limits the output to 'status only', which distinguishes it from content-fetching siblings. However, it names no sibling directly, so the differentiation is implicit rather than explicit.

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 indication of when to prefer this tool over alternatives like web-fetch or browser-url-ok. There is no when-to-use, when-not-to-use, or exclusion of related operations.

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