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

The description discloses one important behavioral trait: no browser is launched. However, with no annotations at all, the description carries the full burden, and it does not mention whether any network request is made, how 'can be opened' is determined, what side effects exist, or what the return value looks like.

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 short and front-loaded, with no filler words. However, given the nine-parameter schema and the absence of an output schema, this level of brevity leaves important information out.

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 is not contextually complete for an agent: there is no output schema, no annotations, and the description does not explain which parameter should be used, what result indicates success, or how the URL check relates to the other accepted parameters. The 'No browser is launched' note is useful but insufficient.

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 structured schema already documents all nine parameters. The tool description adds no parameter-level meaning, and it does not clarify how the many unrelated-looking parameters (city, feed, json, path, zone, query) relate to checking a URL.

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 ('Check') and resource ('whether a URL can be opened'), which gives a usable sense of the tool's purpose. The added note 'No browser is launched' helps differentiate it from browser-based checks, though it does not explicitly name sibling tools or fully 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?

There is no guidance on when to use this tool versus alternatives such as browser-url-ok, fetch-status, or normalize-url. The description implies a lightweight URL check, but it never states the conditions under which an agent should choose this tool or what to pass.

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