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

No annotations are provided, so the description carries the full disclosure burden. It does reveal one behavioral trait ('No browser is launched'), but it leaves many unknowns: whether a network request is made, what the output looks like, whether the operation is read-only, and what happens to the non-URL parameters (many are described as 'discarded' in the schema, but the description doesn't explain that). This is insufficient for a tool with such a broad schema.

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 (one sentence) and front-loads the core purpose and a key behavioral caveat. However, it is so sparse that it sacrifices completeness; the single sentence does not earn its place fully because it leaves too much unstated. It is concise but under-specified, so a 3 is appropriate.

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?

With nine optional parameters, no annotations, and no output schema, this tool requires substantial description to be usable. The description only addresses a single URL check, gives no context on the other parameters, return values, or failure behavior, and does not clarify the relationship to sibling tools. It is severely incomplete for the tool's complexity.

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 parameter-level guidance and does not help interpret the odd mix of parameters (city, feed, zone, etc.) in the context of URL checking. Baseline is 3 because the schema covers the parameters, but the description adds zero value here.

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 ('check') and resource ('a URL'), and adds a distinguishing trait ('No browser is launched'). However, it is vague about what 'can be opened' means (syntactic validation vs. network reachability) and entirely ignores the nine other input parameters, which suggests the tool may do more than check URLs. This ambiguity prevents a higher score.

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?

The description gives no explicit when-to-use or when-not-to-use guidance. It only implies that this is a non-browser variant, but it does not name alternative tools like 'browser-url-ok' or state conditions for choosing between them. An agent has to infer usage from the name and the single sentence.

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