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

With no annotations, the description is the only source for behavioral disclosure. It does state that no browser is launched, which is useful, but it omits whether an HTTP/network request is made, what 'opened' means, what the return value is, and any error/timeout behavior. This is a significant gap for a check tool.

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 filler; purpose is first and the browser disclaimer is a valuable, non-redundant second sentence. This is appropriately concise.

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 description is underspecified for a tool with no output schema and no annotations: an agent cannot tell what result it will get (boolean? status?), what network behavior to expect, or why the schema includes nine optional parameters. It provides enough for a first guess but not reliable invocation.

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 describes all 9 optional parameters, so the description need not repeat them. The description adds no parameter-level semantics beyond the schema, and the unusual mix of discarded fields (ref, city, query, etc.) is left unexplained, but that gap is already covered by parameter descriptions.

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 action and object ('Check whether a URL can be opened') and adds a meaningful constraint ('No browser is launched'). However, 'can be opened' is left undefined—it could mean syntax validation, DNS/network reachability, or HTTP success—so it only partially distinguishes this from fetch-status or web-fetch.

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 explicit guidance about when to choose this tool over browser-url-ok, fetch-status, or web-fetch, and no mention of alternatives. The only hint is the exclusion of browser launch, which weakly implies it is for lightweight checks, but not enough to route an agent correctly.

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