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 does disclose that no browser is launched, but it does not state whether a network request is made, whether there are side effects, what permissions are needed, or what failure modes exist. 'Can be opened' remains vague about the actual behavior.

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 two short sentences with no filler. It front-loads the core action and immediately adds the key behavioral qualifier. Every word earns its place.

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 parameters, no annotations, and no output schema, this one-sentence description is inadequate. It does not explain which parameters are relevant, what 'opened' means, what the tool returns, or when to choose it over sibling tools. The description covers only the most basic purpose.

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 even though the tool description adds no parameter-level meaning. Several parameters like ref, city, json, and query seem unrelated to checking whether a URL can be opened, and the description does not clarify how they relate to the tool's purpose. The schema descriptions help, but the overall parameter story is confusing.

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 action ('Check whether a URL can be opened') and a resource ('a URL'), and adds a useful qualifier ('No browser is launched'). However, 'can be opened' is somewhat ambiguous—it could mean URL syntax validation, network reachability, or browser compatibility—and the description does not explicitly differentiate it from siblings like playwright-url-ok or fetch-status beyond the no-browser note.

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. It does not mention fetch-status, playwright-url-ok, normalize-url, or any other sibling, nor does it state when the tool is or is not appropriate. The no-browser note hints at a distinction but does not provide actionable usage direction.

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