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

No annotations are present, so the description must carry the disclosure burden. It does add one valuable behavioral fact—'No browser is launched'—which prevents the agent from assuming Playwright opens a real browser. But it does not disclose whether a network request is made, what an 'ok' result means, or how errors/failures are represented.

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, and the most decision-relevant constraint ('No browser is launched') is placed prominently after the core action.

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, no output schema, and no annotations, the description is too thin: it doesn't identify which parameter drives the check, what the return value looks like, or how to interpret a 'can be opened' result. The schema shows many unrelated input types (ref, city, json, path, zone, query), so the agent still lacks a complete decision picture.

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 schema already documents all nine parameters, including which are discarded. The description adds no parameter-level meaning, but the baseline of 3 applies because the schema carries that burden.

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 second sentence clarifies the mechanism boundary by saying no browser is launched. However, 'can be opened' could mean URL-shape validity or network reachability, and it doesn't explicitly distinguish from sibling tools like browser-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?

There is no when-to-use guidance, no exclusion criteria, and no named alternatives. With siblings such as browser-url-ok, normalize-url, and fetch-status available, the description leaves the agent to guess when this tool is the right choice.

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