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

With no annotations, the description carries the disclosure burden. It honestly discloses that no browser is launched, which is a meaningful side-effect behavior, but it does not state whether the URL is fetched, how 'ok' is determined, or what side effects (if any) 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 two short sentences with no filler. The core action is front-loaded and the key behavioral caveat follows immediately.

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 seven parameters and no annotations or output schema, this description is too thin. It leaves unanswered what parameters to supply, what result is returned, and what exactly the URL check verifies, especially given unrelated-looking parameters like ref, city, feed, and json.

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 input schema fully describes all seven parameters, and the description adds no parameter-level meaning beyond saying the tool checks a URL. Given high schema coverage, the baseline of 3 applies; the description doesn't clarify which of the many schema fields are relevant to this 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 specific action and object: 'Check whether a URL can be opened.' It also clarifies a key distinguisher, 'No browser is launched,' but does not define what 'can be opened' means or name a sibling tool such as playwright-url-ok, so slight ambiguity remains.

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?

The 'No browser is launched' clause implies this is for quick checks where browser execution should be avoided, but there is no explicit when-to-use guidance, prerequisite, or comparison to alternatives like fetch-status or playwright-url-ok.

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