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

With no annotations, the description must disclose behaviors. It only notes that no browser is launched, but does not clarify whether a network request is made, if the operation is read-only, or what side effects (if any) occur. Schema hints like 'discarded' and 'no disk access' appear in parameter descriptions, but the main description omits these, leaving the tool's behavioral profile vague.

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 sentence with no filler. It immediately states the core action and the key limitation (no browser launch), making it highly efficient and easy to parse.

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 the tool has 9 parameters, no annotations, and no output schema, the description is far too sparse. It does not explain the return value, which parameter is mandatory (though all are optional), or how to interpret 'can be opened.' The mismatch between the simple description and the complex schema makes the tool insufficiently specified for correct use.

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 description does not explain which parameter is the actual URL to check, nor how the many unrelated parameters (ref, city, feed, host, etc.) relate to the tool's purpose. The schema descriptions are cryptic and the main description fails to clarify the role of each parameter, so an agent cannot confidently map inputs to the intended check.

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' and adds a distinguishing trait 'No browser is launched.' However, it does not explicitly contrast with sibling tools like playwright-url-ok, leaving some ambiguity about what 'can be opened' means (e.g., syntactic validity vs. live fetch).

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 on when to use this tool versus alternatives such as normalize-url or fetch-status. The description does not mention conditions, exclusions, or preferred scenarios, leaving the agent to infer usage from the name alone.

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