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

The description only states that no browser is launched, but it does not disclose what the tool actually does (e.g., HTTP request, URL validation). Additionally, it does not mention that many of the parameters are ignored, which is only implied by their individual descriptions.

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 concise (one sentence) and easy to read, but it omits essential details about how the check is performed and what the result represents. The structure is acceptable but not comprehensive.

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 is incomplete for a tool with this complexity. It lacks information about the output format, what 'ok' means (e.g., status code, reachability), and why so many unrelated parameters are present. Without this context, an agent would struggle to use it 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?

The schema includes nine parameters, but most are irrelevant to the stated purpose (e.g., 'ref', 'city', 'feed', 'json', 'zone', 'query'). The only relevant parameter 'url' has a description that says 'HTTPS URL to normalize or cite,' which conflicts with the tool's purpose of checking if a URL can be opened.

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 the tool 'Check whether a URL can be opened,' but it is vague about which parameter is the URL and does not differentiate from sibling tools like 'browser-url-ok' or 'fetch-status' that likely serve a similar 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?

There is no guidance on when to use this tool versus alternatives such as 'browser-url-ok' or 'fetch-status.' No context is given about the appropriate use case.

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