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

With no annotations provided, the description carries the full behavioral burden. It usefully discloses that no browser is launched, but it does not say whether a network request is made, how 'openable' is determined, whether authentication is needed, or what side effects might occur.

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 front-loaded sentence that states the core function and adds the key caveat about not launching a browser. Every word earns its place; there is no wasted or redundant content.

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 having no output schema, no annotations, and nine optional parameters, the description does not explain return values, success criteria, or how the many unrelated-looking parameters relate to the URL check. An agent has too much left to infer.

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 the parameters are already individually documented and the description does not need to repeat them. The tool description adds no extra parameter-level meaning, so the baseline score of 3 is appropriate.

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 action and resource: check whether a URL can be opened. The 'No browser is launched' clause helps distinguish it from browser-launching siblings like playwright-url-ok, though it does not explicitly name the alternative or define what 'can be opened' means.

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 an implied usage cue: because no browser is launched, an agent can infer this is the lightweight check and that browser-based rendering is not needed. However, it never explicitly states when to choose this tool over siblings like fetch-status, normalize-url, or playwright-url-ok.

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