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

There are no annotations, so the description carries the full burden of behavioral disclosure. It reveals one trait, that no browser is launched, but leaves unclear whether a network request is made, what side effects exist, what the return value looks like, or why several parameters are 'discarded after the call.'

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?

Two short sentences with no wasted words; the main action is front-loaded and the caveat follows immediately. This is appropriately sized for what it communicates.

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?

The tool has seven heterogeneous parameters, no annotations, and no output schema, so a complete description would need to explain return behavior and how the parameters map to the tool's purpose. The description does neither, and the unrelated-looking parameters create ambiguity about what the tool actually checks.

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 provides descriptions for all seven parameters, so high schema coverage means the description is not required to restate them. The description adds no parameter-level meaning and fails to explain how the URL parameter relates to ref, city, feed, host, json, and path, but the schema text does provide partial semantic coverage.

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 an important qualifier ('No browser is launched'), so the core operation is clear. It does not, however, differentiate this tool from siblings like fetch-status or playwright-url-ok, and the schema includes non-URL params (ref, city, json, path) that the description does not reconcile.

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 browser is launched' implies this is a lighter-weight alternative to browser-driven checks, but no sibling tool or explicit when-to-use/when-not-to-use guidance is provided. The usage intent is implied rather than stated, leaving the agent to guess when this is preferable to normalize-url, 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.