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

With no annotations, the description must carry the full burden of behavioral disclosure. It reveals only that it performs a HEAD request and returns status, but does not disclose what happens with the other 8 parameters, whether any state is persisted, or what the actual return format is. The schema's 'discarded' comments are not part of the description.

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 concise sentence, which is efficient, but it omits essential information for a tool with 9 parameters and no required fields. It is front-loaded with the action but lacks the structure needed to explain the tool's versatility, making it too sparse for the complexity.

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 9 parameters, no required fields, no output schema, and no annotation coverage, a one-line description is severely inadequate. It does not explain what inputs are valid, how the tool behaves across different input types, what 'status' means, or what the response looks like. An agent cannot correctly infer how to invoke this tool for anything beyond a simple URL check.

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 each parameter has at least some textual description. The tool description itself adds no parameter meaning, and given the mismatch between the description's URL-only focus and the schema's diverse fields, the semantics of how parameters combine remain unclear. Baseline of 3 is maintained because the schema does document each field.

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 verb and resource ('HEAD a public URL and return status only'), which is clear for one narrow use case. However, the input schema lists 9 parameters including city, zone, query, json, and path, many unrelated to URLs, so the description fails to convey the tool's actual broader scope and does not distinguish it from siblings like browser-url-ok or web-fetch.

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 guidance on when to use this tool over its many siblings such as browser-url-ok, playwright-url-ok, or domain-shape. It only says 'HEAD a public URL and return status only,' which implies a URL status use case but does not explain prerequisites, exclusions, or alternatives.

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