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

No annotations are provided, so the description carries the full burden. It only reveals that no browser is launched; it does not disclose whether a network request occurs, how the check is performed, what 'ok' means, what the return value is, or whether there are side effects.

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?

Two short sentences with no filler. The main purpose is stated first and the key behavioral constraint is front-loaded in the second sentence, making it efficient and scannable.

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?

With no annotations, no output schema, and 9 optional parameters, this description is too sparse to be complete. An agent is not told what the tool returns, what conditions indicate success or failure, or how it relates to similar sibling tools, leaving important gaps.

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 schema already documents all 9 parameters, including discard behavior. The tool description itself adds no parameter-level meaning, but the baseline of 3 applies because the schema carries the necessary semantics.

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 ('Check whether a URL can be opened') and identifies the resource (URL), with an added clarifying trait ('No browser is launched'). However, it does not differentiate this tool from the sibling 'browser-url-ok' or explain what 'opened' means operationally.

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 alternatives. 'No browser is launched' hints at a browserless context, but it does not explicitly say when to prefer this over browser-url-ok, fetch-status, or normalize-url, nor does it give exclusions.

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