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

With no annotations, the description carries the full burden, but it only discloses one behavioral fact: no browser is launched. It does not state whether the tool performs a network request, validates syntax, returns a boolean, requires authentication, or what side effects may occur.

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 and front-loads the central action, with no filler. However, given the nine optional parameters and sibling ambiguity, the brevity is borderline under-specification rather than ideal concision.

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?

There is no output schema and no mention of return values, typical call patterns, or why the many optional parameters exist. For a 9-parameter tool with many closely named siblings, this description is not complete enough for an agent to select and invoke it confidently.

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 input schema already documents each of the nine parameters. The tool description adds no parameter behavior or relationships, leaving the schema to do the work; baseline 3 is appropriate.

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 gives a specific action ('Check') and object ('whether a URL can be opened'), so the core purpose is clear. It does not, however, explain how this differs from closely related siblings such as browser-url-ok or fetch-status, and 'opened' is ambiguous without more detail.

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 provided about when to prefer this tool over browser-url-ok, fetch-status, normalize-url, or other siblings. The caveat 'No browser is launched' hints at a lightweight check but stops short of saying when it should or should not be used.

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