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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It explicitly states that no browser is launched, but fails to say whether the tool makes a network request, accesses the file system, returns diagnostic info, or has side effects. Nested schema hints like 'no disk access' and 'discarded after' appear in parameter descriptions, but these aren't surfaced in the tool description and don't clarify the tool's overall 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?

Two short sentences with the purpose stated first, followed by a useful caveat: 'No browser is launched.' No filler words, every sentence earns its place, and the core idea is front-loaded.

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?

This is a 9-parameter, optional input check tool with no output schema and no annotations. The description doesn't explain what the tool returns, what a 'can be opened' verdict looks like, or how to interpret the check, nor does it reconcile the presence of unrelated_parameters. The description is under-specified for an agent to call it confidently.

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. The tool description adds no parameter-level meaning; it just states the overall purpose. The individual parameter descriptions are already present and adequate, so the tool description doesn't need to compensate, but it also provides no extra clarity on why many seemingly unrelated params (city, zone, json, feed) are accepted for a URL 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?

Description clearly states the action 'Check whether a URL can be opened' with a specific resource (a URL) and a distinguishing behavioral note that no browser is launched. It doesn't name sibling tools, leaving some ambiguity about what 'can be opened' means versus fetch-status or normalize-url, but the core purpose is specific and not a tautology.

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 rather than the many siblings like playwright-url-ok, fetch-status, or normalize-url. 'No browser is launched' is a behavioral trait, not a usage condition. With 29 siblings and no exclusions or alternatives, the agent is left to infer appropriate usage.

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