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

With no annotations, the description must disclose behavior. It claims to check if a URL can be opened but then says 'No browser is launched', which is contradictory and leaves unclear what mechanism is used. It does not disclose whether it performs a network request, validates syntax, or returns a status. This is a significant 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 brief (two sentences), but brevity is not conciseness; it omits critical information. The main claim is front-loaded, but the lack of detail makes it under-specified rather than efficiently 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?

Given 9 parameters, no output schema, and no annotations, the description is grossly incomplete. It does not explain what the tool returns, which parameters are relevant to the URL check, or how the other parameters are used. An agent cannot determine correct usage without external knowledge.

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 coverage is 100%, so each parameter already has a description. The tool description adds no extra meaning about how the parameters relate to the URL check. The baseline of 3 is appropriate because the schema does the heavy lifting, though the tool description fails to clarify the purpose of the many seemingly unrelated parameters.

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 clear verb and resource ('Check whether a URL can be opened'), but it is ambiguous about what 'opened' means (validity, reachability, HTTP status). It does not differentiate from siblings like 'browser-url-ok' or 'web-fetch', and the parameter list includes many unrelated fields (city, json, path) that are not explained. This is a clear but vague purpose.

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 given on when to use this tool versus its siblings. The description does not mention any conditions, alternatives, or exclusions. An agent has no way to know if this is preferable to 'browser-url-ok' or 'web-fetch'.

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