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

With no annotations, the description must carry the behavioral burden, and it does provide one valuable disclosure: no browser is launched. However, it is silent on whether a network request is made, what the return value looks like, and how errors are surfaced, so transparency is only partially covered.

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?

Two sentences with no filler: the main purpose is front-loaded and the no-browser qualifier earns its place as an important disambiguation. It is terse to the point of underspecification given the nine-parameter schema, but that is more a completeness gap than a conciseness flaw.

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?

No output schema, no annotations, and a short description leave core invocation questions unanswered: which parameter to pass, what a successful check returns, and how this tool differs from browser-url-ok or fetch-status. The description alone is not sufficient for reliable tool selection and invocation.

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 the baseline is 3 even though the tool description adds no parameter-level meaning. The schema already documents each field, but the tool description's 'URL' framing is not reflected in several unrelated parameters, which can confuse selection of the right input.

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 names a concrete operation ('check whether a URL can be opened') and adds a decisive qualifier that no browser will be launched, which separates it from browser-url-ok. It stops short of defining what counts as 'opened' or which schema field carries the URL, so it is clear but not complete.

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?

There is no explicit guidance on when to use this tool versus closely related siblings like browser-url-ok, fetch-status, or web-fetch. 'No browser is launched' is an implied trait, but the description does not name alternatives or describe the conditions that should route an agent to this tool.

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