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

With no annotations, the description carries full responsibility for disclosing behavior. It only states that no browser is launched, but does not mention whether network requests are made, what the return value looks like, side effects, or how parameters are used. The schema descriptions for many parameters say 'discarded after', which is confusing and not addressed in the tool description.

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 a single sentence, which is concise but severely under-specified for a tool with nine parameters. It lacks any structural breakdown, examples, or elaboration on the check process. Brevity is not an asset when it leaves critical information missing.

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 tool's complexity (nine parameters, no output schema, no annotations), the description is grossly inadequate. It does not explain what the tool returns, error conditions, how to use the parameters, or any behavioral nuances. An agent cannot reliably invoke this tool correctly based on the provided information.

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 the baseline is 3, but the description adds no meaning beyond the schema. It fails to explain why the tool accepts parameters like city, json, zone, or query when its stated purpose is URL checking. The schema descriptions themselves are vague (e.g., 'discarded after') and the tool description does not clarify their role, making the parameters semantically unclear.

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') and adds a clarifying note about no browser launch. However, it does not specify what 'opened' means (e.g., HTTP status, reachability, format) and does not differentiate from siblings like 'browser-url-ok' or 'fetch-status'. The presence of nine parameters, many unrelated to URLs, further muddies the purpose.

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 is given on when to use this tool versus alternatives. The only hint is 'No browser is launched', implying a lightweight check, but there is no explicit comparison with siblings or conditions that would select this tool over others.

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