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 discloses one useful fact ('No browser is launched'), but it does not say whether an HTTP request is made, what counts as 'ok', whether the URL is modified or cited, or what the tool returns. This is minimal disclosure, not adequate transparency.

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 two short sentences with the core action front-loaded and no filler. It is concise to a fault because it omits behavioral and output details, but the structure itself is efficient and an agent can parse the main point immediately.

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?

The tool has nine optional parameters, no output schema, and no annotations, so an agent needs more context about what result to expect and which parameter to use. The description only gives the high-level check and omits return semantics, success criteria, and guidance on how the unrelated parameters relate to the URL check.

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 has 100% description coverage for all nine parameters, so the schema already documents each parameter. The description adds no parameter-level meaning and does not clarify which parameter is central to the URL check, but it does not need to compensate heavily given the high schema coverage.

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 uses a specific verb and resource ('Check whether a URL can be opened') and adds a key differentiator ('No browser is launched'), which helps distinguish it from browser-url-ok. However, 'can be opened' is somewhat vague, and the schema's nine unrelated parameters suggest the actual tool scope may be broader than the description implies.

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 phrase 'No browser is launched' implies a lightweight URL check, which is a clear context signal for choosing this tool over a browser-based alternative. But it does not explicitly name alternatives like browser-url-ok or fetch-status, nor does it state when not to use this tool.

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