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

No annotations are provided, so the description must carry the full behavioral burden. It only says 'HEAD a public URL and return status only' – it does not disclose side effects, limitations, what happens with the other eight parameters, or the format of the returned status. This is insufficient for a tool that clearly accepts many kinds of inputs.

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 extremely concise – a single sentence with no fluff. However, this brevity comes at the cost of omitting essential context about the tool's broader parameter usage. It is appropriately front-loaded but under-specifies the tool's behavior.

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?

With nine optional parameters, no output schema, and a one-sentence description, the tool is significantly under-documented. An agent cannot understand what the tool does with most parameters, what constitutes a valid call, or what the response structure looks like. The description only covers a fraction of the tool's apparent capabilities.

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 coverage is 100%, so the schema describes all parameters, but the description adds no value beyond that. Worse, the description's claim of 'HEAD a public URL' directly conflicts with the presence of parameters like 'city', 'zone', and 'json', which suggest the tool does more than URL checking. The description misrepresents the tool's actual parameter semantics.

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 (HEAD a public URL) and a clear outcome (return status only), which distinguishes it from some siblings. However, the input schema includes nine unrelated parameters (city, zone, json, path, etc.) with no mention in the description, creating confusion about the tool's actual scope. The purpose is clear only for a narrow URL-check use case, not for the broader parameter set.

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 provides no guidance on when to use this tool versus its many siblings (normalize-url, browser-url-ok, web-fetch, etc.). It does not mention alternatives or conditions for selection. The absence of any when-to-use or when-not-to-use information leaves the agent to guess based solely on the tool name.

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