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

With no annotations provided, the description must carry the full behavioral burden. It does disclose one meaningful behavior—no browser is launched—but it does not say whether a network request is made, whether the check is purely syntactic, whether the tool is side-effect free, or what happens if the URL is invalid. This is too thin for a tool without annotation support.

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 very concise: two short sentences with no filler, wasted words, or repetition. The core operation is stated first, and the important caveat about not launching a browser follows immediately, which is good front-loading for a definition this simple.

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?

Despite the concise overall format, this tool has 9 optional parameters, no output schema, and no annotations, so contextually the description is insufficient. The description fails to explain what the result of 'can be opened' looks like, which parameters are relevant to the main URL check, and how the many unrelated-looking discarded parameters factor into the tool's behavior.

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?

All nine parameters have descriptions in the schema, so schema description coverage is 100%, which sets the baseline at 3. The tool description itself adds no parameter-level guidance and does not clarify how parameters like city, query, or zone relate to 'checking whether a URL can be opened,' but the schema already provides descriptions for each parameter.

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 clearly identifies the action—checking whether a URL can be opened—and adds a meaningful qualifier that no browser is launched. This helps distinguish it from browser-launching tools like playwright-url-ok, though it does not explicitly differentiate it from similar URL status tools such as fetch-status 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?

There is no guidance about when to use this tool versus siblings like playwright-url-ok, fetch-status, or normalize-url. The phrase 'No browser is launched' is a behavioral hint rather than an explicit routing instruction, so an agent gets little help choosing among the many closely related alternatives listed.

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