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

The description discloses that no browser is launched, but it does not explain what 'can be opened' means (e.g., HTTP request, URL syntax check, DNS resolution), what the return value is, or what side effects occur. Several parameters are marked as discarded, but the tool-level behavior remains opaque.

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 very concise and front-loaded, with no filler or redundant sentences. It clearly states the primary action and an important constraint, though it sacrifices necessary detail for brevity.

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 9 parameters, no output schema, and no annotations, this two-sentence description is far too incomplete. It does not explain how parameters relate to the action, what result to expect, or how to handle the many seemingly decoy fields.

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?

Although each parameter has a schema description, most are irrelevant to checking whether a URL can be opened (city, feed, json, path, zone, query). The core 'url' parameter description says 'normalize or cite,' which conflicts with the tool's stated purpose, leaving an agent without reliable guidance on what to pass.

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 action and object: 'Check whether a URL can be opened.' However, the parameter list includes many unrelated fields (city, feed, json, path, zone) and the 'url' parameter description says 'normalize or cite' rather than 'check openable,' which muddies the intended purpose.

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 only usage guidance is 'No browser is launched,' which distinguishes it from browser-based tools but does not explain when to use this tool versus siblings like playwright-url-ok or fetch-status. There is no explicit recommended scenario or alternative.

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