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

The only behavioral trait disclosed is 'No browser is launched,' which is a negative constraint. It does not explain what the tool actually does (e.g., HTTP request, DNS lookup) or that many parameters are discarded after checks. With no annotations, the description fails to carry the burden of behavioral disclosure.

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 very short (two sentences) and therefore concise, but it is under-specified for a tool with 9 parameters. It omits essential details about parameter roles and the tool's actual operation, making it insufficient rather than appropriately concise.

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?

With no annotations, no output schema, and 9 parameters, the description is extremely incomplete. An agent cannot determine what the tool returns, how the parameters are used, or what 'URL can be opened' means in practice. The description does not meet the needs of a complex tool.

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 input schema has 100% description coverage for all 9 parameters, so the baseline is 3. The tool description adds nothing about parameters but also does not mislead. However, it fails to clarify why unrelated parameters (e.g., city, json, zone) exist in a URL-checking tool.

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 'Check whether a URL can be opened' which is a verb+resource, but 'can be opened' is vague (does it mean HTTP status, DNS resolution, or something else?). It also doesn't distinguish this tool from siblings like browser-url-ok or fetch-status, and it completely ignores the 9 parameters, many of which are unrelated to URL checking.

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 about when to use this tool versus alternatives. There is no mention of exclusions, conditions, or which sibling tools might be more appropriate for specific scenarios.

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