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

It discloses that no browser is launched and that many parameters are 'discarded,' which is helpful. However, it does not mention that checking a URL likely involves a network request, nor does it describe error behavior or side effects like latency.

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 a single, concise sentence that immediately states the action and an important caveat. It is easy to read and contains no fluff.

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 description is too sparse to be complete given the tool's complex schema and the existence of many sibling tools. It lacks a definition of what 'opened' means, what the return value is, and why unrelated parameters are accepted. No output schema is provided, further reducing completeness.

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 parameter descriptions are misleading and misaligned with the tool's stated purpose. The 'url' description says 'normalize or cite' rather than 'check accessibility,' and the other parameters (city, feed, zone, query, etc.) are irrelevant to URL checking, even if marked as discarded. The schema coverage is 100% but the content actively confuses.

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 core action is clear: check whether a URL can be opened. The note that no browser is launched adds implementation clarity, but 'can be opened' is left ambiguous (HTTP status, DNS resolution, etc.), so it is not fully precise.

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 guidance on when to use this tool versus the many related siblings (e.g., fetch-status, normalize-url, domain-shape). It does not specify typical scenarios or when to avoid it, leaving selection to the agent.

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