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 only states 'No browser is launched,' which is a negative constraint, but it does not describe what the check actually does (e.g., network request, DNS resolution, HTTP status) or any side effects. The schema hints at 'shape check' and 'discarded after' but the description adds no clarity, leaving the behavior opaque.

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 short sentence, which is concise, but it is severely under-specified. It lacks any structure to guide usage and does not earn its place by providing necessary information. The brevity here is a deficiency, not a virtue, given the tool's complexity.

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 9 optional parameters, no annotations, and no output schema, this description is wholly inadequate. It does not explain how the parameters relate to the operation, what constitutes a successful check, or how to interpret results. The tool is effectively a black box with a misleadingly simple description, leaving the agent unable to call it correctly.

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 baseline is 3, but the description adds no value in interpreting the parameters. It does not indicate which parameter is the primary URL input or how the various unrelated parameters (city, json, zone) relate to the stated purpose. The schema descriptions themselves are confusing (e.g., 'Git ref name; discarded after the shape check'), and the tool description fails to reconcile them with the claimed URL check.

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'), which is specific. However, the input schema contains 9 unrelated parameters (ref, city, feed, json, path, zone, etc.), and the description does not clarify which parameter represents the URL to check. This ambiguity undermines the purpose clarity, especially given the many sibling tools with similar URL-related functions (e.g., fetch-status, normalize-url).

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 description offers no guidance on when to use this tool versus alternatives. It does not mention any sibling tools, conditions, or exclusions. There is no context about the intended use case or how to select the correct parameter for the URL check, leaving the agent without direction.

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