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

With no annotations provided, the description carries the full burden of disclosing side effects and behavior. It only states that no browser is launched, but it does not mention network requests, potential external calls, latency, failure modes, or any other behavioral consequences of checking a URL.

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 brief and to the point, with no redundant fluff. The two sentences are easy to read and front-load the core purpose. However, the brevity comes at the cost of omitting necessary context about parameters and usage.

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 the mismatch between the description and the input schema, and the absence of an output schema or annotations, the description is not enough for an agent to understand what inputs are actually used, what results to expect, or how this tool fits into the broader toolset. Critical context is missing.

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 contains nine optional parameters, but most have descriptions that are irrelevant or contradictory to the stated purpose. For example, 'url' is described as 'HTTPS URL to normalize or cite' rather than to check, and fields like 'ref', 'city', 'feed', 'json', 'path', 'zone', and 'query' appear to be unrelated leftovers from other tools. This creates significant ambiguity about which parameters actually matter.

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-resource pair ('check whether a URL can be opened') and adds a useful negative behavior ('No browser is launched'), which helps distinguish it from browser-based sibling tools. However, 'can be opened' is ambiguous—it could mean HTTP reachability, validity, or something else—and it does not name the specific sibling tools it contrasts with.

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 about when this tool should be chosen over alternatives like playwright-url-ok, fetch-status, or normalize-url. The only hint is the negative statement about not launching a browser, which is insufficient for an agent to decide when to invoke this tool.

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