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

With no annotations, the description carries full behavioral disclosure. It only notes 'No browser is launched' but fails to clarify whether a network request occurs, what side effects exist, how the various parameters are used, or what the return value looks like. The mention of parameters being 'discarded' is only in the schema, not the 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 concise sentence, which is efficient. However, it lacks structure that would help an agent quickly grasp the tool's full scope—there is no breakdown of the diverse parameters or usage context. It is under-specified rather than well-structured.

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 9 parameters, no annotations, and no output schema, the description is severely incomplete. It does not explain how the majority of parameters are used, what the tool actually validates, or how it differs from siblings. An agent cannot reliably determine whether to invoke this tool for inputs like JSON or timezone names.

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 schema descriptions fully cover each parameter (100% coverage), so the baseline is 3. However, the tool description adds no value to parameter understanding and actually creates confusion by focusing only on URL while the schema includes many other input types. It does not explain how these parameters relate to the stated purpose.

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 specific verb and resource ('Check whether a URL can be opened'), which gives a clear core purpose. However, the input schema contains 9 unrelated parameters (city, json, zone, etc.) that are not mentioned, making the tool's actual scope ambiguous. It does not distinguish itself from siblings like browser-url-ok or 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?

There is no guidance on when to use this tool versus alternatives. The description does not mention any conditions, exclusions, or comparisons to sibling tools, leaving the agent to infer usage context on its own.

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