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

No annotations are provided, so the description carries the full burden. The description says it HEADs a public URL, but the schema contains nine unrelated parameters (ref, city, feed, json, path, zone, query) whose descriptions reference other tools ('discarded after shape check', 'weather hint', 'validate', etc.). The description does not disclose that only 'url' is meaningful or that all other parameters are ignored, making actual behavior highly opaque.

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 a single, short sentence that is front-loaded with the core action and output. It contains no fluff or redundant wording, earning every word.

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 tool with no output schema and a polluted input schema, the description is incomplete. It does not clarify that 'url' is the required parameter, that all other parameters are ignored, or what 'status only' means in terms of the return value (e.g., HTTP status code, reason phrase). This creates significant ambiguity for an agent trying to invoke the tool correctly.

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?

Although every parameter has a description, those descriptions are inconsistent with the tool's stated purpose. For example, 'url' is described as 'HTTPS URL to normalize or cite' rather than the target of a HEAD request, and parameters like 'city' and 'zone' reference weather/timezone hints. The schema gives no indication of which parameters are actually used or required.

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 and resource: 'HEAD a public URL and return status only.' This clearly distinguishes it from siblings like web-fetch (which retrieves content) and status-catalog (which lists statuses). The 'status only' output is a crisp, unambiguous purpose.

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 does not explicitly explain when to use this tool versus alternatives such as browser-url-ok, normalize-url, or web-fetch. It implies use for lightweight status checks, but it never names sibling tools or conditions like 'use this when you only need the HTTP status code.'

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