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

With no annotations, the description carries the full burden of behavioral disclosure. It only states 'No browser is launched', which is a negative claim that raises more questions than it answers (e.g., how is the check performed? what side effects occur? what does 'ok' mean?). No information is given about permissions, error handling, or return format.

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 short, but it is under-specified rather than concise. It omits critical context and provides only a vague claim. While brevity is good, it fails to earn its place by conveying necessary information.

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?

Given 9 parameters, no annotations, and no output schema, the description is severely incomplete. It does not explain what the tool returns, how to interpret results, or what constraints apply. For a tool with such a broad schema, this is wholly inadequate.

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?

Although schema coverage is 100%, the description adds nothing about the parameters. It does not explain why parameters like 'city', 'zone', 'json', or 'query' appear in a URL-checking tool, nor how they relate to the check. The schema descriptions are terse and the tool description offers no clarification, so the odd parameter set remains confusing.

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') but immediately contradicts it with 'No browser is launched', leaving the actual behavior ambiguous. It does not distinguish itself from siblings like browser-url-ok or fetch-status, which likely have overlapping purposes. The verb and resource are present but the meaning is muddled.

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 is provided on when to use this tool versus the many similar shape-checking siblings (e.g., browser-url-ok, domain-shape, normalize-url). There is no mention of prerequisites, alternatives, or exclusion criteria. An agent has no basis for selecting this over its peers.

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