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

With no annotations, the description carries the full burden of behavioral disclosure. It usefully states that no browser is launched, but it does not explain whether a network request is made, whether the operation is read-only, or what the result indicates.

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 appropriately concise, with two short sentences and the key negative behavior ('No browser is launched') front-loaded. It wastes no words, though it sacrifices necessary guidance for brevity.

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?

Given the seven-property schema and the lack of an output schema, the description is too sparse. It omits which parameter to use, what the check returns, and how this differs from related URL tools, so an agent would have difficulty calling 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 description adds no parameter-level meaning and does not identify which schema property is the URL to check. Although the schema describes each property, the 'url' description is generic ('HTTPS URL to normalize or cite') and misaligned with this tool's purpose, leaving the agent to guess.

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 specific action and resource: 'Check whether a URL can be opened.' This clearly identifies the core function, and the addition of 'No browser is launched' helps signal lightweight behavior. However, it does not explicitly differentiate this tool from siblings like playwright-url-ok, web-fetch, or fetch-status.

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 on when to use this tool versus alternatives such as normalize-url, playwright-url-ok, or fetch-status. It also does not mention which of the seven input properties should be supplied for this check.

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