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

With no annotations present, the description carries the full burden. It discloses that no browser is launched and some parameters are discarded or involve no disk access, but it does not clarify network effects, validation behavior, or why such disparate parameters are accepted.

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 extremely concise and easy to read, with no redundant prose. It loses some structure points because the terse text contradicts the breadth of the input schema, but as a standalone description it is well-formed.

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 nine optional parameters spanning URLs, git refs, timezones, JSON, file paths, and search text, plus no output schema, the description is far too thin to give an agent enough context to invoke the tool correctly or interpret its result.

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?

Although schema coverage is 100%, the parameter descriptions are confusingly heterogeneous (normalize/cite, shape check, length check, no disk access) and do not coherently explain how each field relates to checking whether a URL can be opened. This adds more confusion than semantic value.

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 whether a URL can be opened') but the input schema exposes nine unrelated optional fields (ref, city, json, zone, query, etc.), making the tool's actual purpose ambiguous and hard to distinguish from siblings like fetch-status or playwright-url-ok.

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 when-to-use guidance is provided; the description does not mention alternatives or explain when this tool should be preferred over related tools. The only extra note ('No browser is launched') is a behavioral constraint, not usage direction.

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