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 only states the tool checks URL openness and that no browser is launched. It does not disclose whether network requests are made, what happens with the auxiliary parameters, whether there are side effects, rate limits, or what the response looks like. This is a severe omission for a tool with nine parameters.

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 only two sentences and is front-loaded with the core purpose, which is good for conciseness. However, it is under-specified to the point of being unhelpful; the second sentence about no browser is a differentiator but does not earn its place because it lacks context. It is concise but not effectively structured for an agent to act on.

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?

For a tool with nine optional parameters, no output schema, and no annotations, the description is grossly incomplete. It does not explain the tool's overall behavior, the role of each parameter, expected inputs, return values, or error cases. An agent cannot confidently invoke this tool correctly based on the description alone. The complexity demands far more context.

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 coverage is 100% so each parameter has a description, but the tool description adds no additional meaning. It does not explain why parameters like 'city', 'zone', 'json', or 'path' are relevant to checking a URL, nor how they are used or discarded. The descriptions in the schema are terse and the tool description provides no cross-referencing, leaving agents to infer relationships. The description fails to compensate for the unusual parameter set.

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 verb and resource ('Check whether a URL can be opened'), but the presence of nine unrelated parameters (city, zone, json, path, query, etc.) muddies the purpose. It does not clarify how these parameters relate to URL checking or what 'can be opened' means operationally. Differentiates from siblings only by 'No browser is launched', which is minimal.

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?

No guidance on when to use this tool versus alternatives. The only hint is 'No browser is launched', which implies it might be for lightweight checks, but it does not explicitly name browser-url-ok or any other sibling, nor does it state conditions for preferring this tool. Lacks any when/when-not direction.

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