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

With no annotations, the description carries the burden of behavioral disclosure, but it only discloses that no browser is launched. It does not state whether a network request occurs, whether the operation is side-effect-free, how redirects or errors are handled, or what observable result 'ok' means.

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, front-loading the core action and then adding the key behavioral caveat. Every word earns its place.

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 9 parameters, no output schema, and no annotations, two sentences are not enough. The agent is not told what the tool returns, what checking entails, or how this relates to the many sibling URL/status tools, so the description is incomplete.

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 description itself adds no parameter-level meaning, but every parameter already has an explanation in the schema, including notes like 'discarded after the shape 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 names a clear operation ('Check whether a URL can be opened') on a specific resource, and adds a distinguishing negative ('No browser is launched') that separates it from browser-based siblings such as browser-url-ok. It is not quite a 5 because it does not explicitly name the alternative tool or define what 'opened' means in observable terms.

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 when-to-use guidance is provided. The only contextual hint is 'No browser is launched,' which implies choosing this over a browser-driven check, but it never states when this tool should be preferred to fetch-status, normalize-url, web-fetch, or browser-url-ok.

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