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

With no annotations provided, the description carries the full burden of behavioral disclosure. It does state that no browser is launched, which is useful, but it does not say whether the tool makes a network request, what it returns, whether it mutates anything, or how 'can be opened' is determined. This is a significant transparency gap for a tool that may perform remote checks.

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, front-loaded sentence that states the core action and a key qualification. Every word earns its place, and there is no repetition or filler. The only downside is that its brevity leaves out important context, but that is penalized under other dimensions.

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 no output schema, no annotations, and 9 schema parameters, this description is underspecified. It does not mention what result format the agent should expect, how to choose among parameters, or how this tool relates to siblings like playwright-url-ok or fetch-status. An agent would need additional inference to call it confidently.

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 schema description coverage is 100%, so the baseline is 3 even though the description itself adds no parameter-level information. The description does not help an agent decide which of the 9 optional parameters to supply, especially since several seem unrelated to URLs. The schema handles parameter documentation, but the description misses an opportunity to clarify selection.

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 states the tool's action ('Check whether a URL can be opened') and adds a distinguishing behavior ('No browser is launched'). This separates it from browser-based siblings like playwright-url-ok. However, the schema contains many unrelated parameters (city, json, path, zone, query), so the overall purpose is somewhat diluted for an agent inspecting the full definition.

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 phrase 'No browser is launched' implies when this tool is appropriate versus a browser-launching alternative, but it does not explicitly name sibling tools or state conditions for use. There is no clear 'use this when...' guidance, leaving the agent to infer context from the name and one negative statement.

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