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

The description only states that no browser is launched, which is a minimal behavioral disclosure. It does not mention whether network requests are made, whether the tool is read-only, what side effects might occur, or what happens on failure. Without annotations, the description carries the full burden and falls short.

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 short, but it is not well structured or informative. It omits essential context about parameters and behavior, making the brevity a drawback rather than a strength.

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 tool has nine parameters, no output schema, and no examples or return-value information. The description is far too sparse to let an agent call this tool correctly, especially given the apparent mismatch between the description and the parameter list.

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?

While the schema covers 100% of the parameters, most descriptions are terse and inconsistent with the stated URL-checking purpose. For example, 'url' is described as 'HTTPS URL to normalize or cite' rather than something to check, and parameters like city, zone, and query are not explained in relation to the tool's purpose.

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 verb and object ('Check whether a URL can be opened'), but the input schema contains nine largely unrelated parameters (e.g., city, timezone, query), creating significant confusion about the tool's actual scope. The name suggests URL checking, but the schema and descriptions do not align with that 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?

No guidance is given about when to use this tool versus sibling tools such as fetch-status, normalize-url, web-fetch, or playwright-url-ok. There is no indication of which situations prefer this tool over alternatives, nor any exclusions.

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