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

With no annotations provided, the description carries the full burden of behavioral disclosure. It only states a negative ('No browser is launched') and omits what 'check' entails—whether it validates URL format, performs a network request, returns a status, or has side effects on the many parameters. This is a major gap.

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 extremely short (two sentences) with no redundancy, but the second sentence is a bare negation that could be more informative. It is minimal but lacks substance; the brevity does not earn high marks because it omits critical context.

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 nine parameters, no output schema, and no annotations, this description is drastically incomplete. It does not explain what the tool does with parameters like 'ref', 'city', or 'query', what the result looks like, or any prerequisites. Agents would be forced to guess or probe.

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 all nine parameters are individually documented. The tool description adds no additional meaning beyond the schema, so it meets the baseline for high coverage but does not elevate it.

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?

States a clear action ('Check whether a URL can be opened') and adds a distinguishing negative constraint ('No browser is launched'), which hints at its non-browser nature. However, it does not explicitly differentiate from siblings like browser-url-ok or fetch-status, so it misses a point for specificity.

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 guidance on when to use this tool versus alternatives. The description does not mention conditions, exclusions, or alternatives, leaving the agent to infer usage based on the tool name alone.

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