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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It does add one meaningful behavior: 'No browser is launched.' However, it does not explain whether the tool makes a network request, what 'can be opened' means, what the return value looks like, or what happens on failure. This leaves important behavioral expectations unstated.

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 one short sentence with the core purpose front-loaded and no filler. Every word earns its place, and the behavioral note 'No browser is launched' is placed immediately after the purpose. This is appropriately concise for such a small tool.

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 accepts 8 string parameters with no output schema, yet the description does not explain how those parameters relate to checking a URL, which parameter is required, or what the result means. It also does not position the tool among its many shape-focused siblings. The description is too sparse to fully guide correct invocation given the schema's complexity.

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 input schema has descriptions for all 8 parameters, so schema coverage is 100%. The tool description itself adds no parameter-level meaning, which yields the baseline score of 3. The schema descriptions do clarify that many fields are discarded, but the description does not help an agent understand which parameter to pass for the stated URL check.

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 names a clear action and resource: 'Check whether a URL can be opened.' It also distinguishes itself from a sibling by adding 'No browser is launched,' which separates it from something like playwright-url-ok. It does not explicitly name any sibling, but the core purpose is understandable.

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 about when to use this tool versus alternatives like playwright-url-ok, normalize-url, or web-fetch. It does not state prerequisites, exclusions, or conditions that would route an agent here. The only usable hint is the negative side-effect 'No browser is launched,' which is not enough to select among siblings.

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