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

With no annotations, the description must disclose behavior itself. It only says no browser is launched, but does not state whether the check performs a network request, what success/failure looks like, whether the input is validated locally, or what side effects occur. The 'discarded' schema notes are not part of the tool description.

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 no filler; the primary purpose is front-loaded and the no-browser caveat is useful. It is concise, though somewhat at the expense of necessary detail.

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?

For a tool with nine optional heterogeneous parameters and no output schema, the description is incomplete. It omits the return value, error/status behavior, which parameter is required for the URL check, and how it relates to the many sibling tools.

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 coverage is 100%, but the schema itself is confusing for this tool: 'url' is described as 'HTTPS URL to normalize or cite' and several other optional params (ref, city, feed, json, path, query) are unrelated to the stated purpose. The description adds no mapping from its purpose to any parameter, so an agent cannot tell which field to populate.

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 clear action and object: 'Check whether a URL can be opened,' and adds a differentiator in 'No browser is launched.' It does not fully explain what 'opened' means (syntax check vs reachability), but it is specific enough to separate from browser-launching siblings.

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 guidance on when to choose this tool over siblings like playwright-url-ok, fetch-status, or normalize-url. The no-browser sentence hints at a lightweight use case, but no explicit when/when-not conditions or alternatives are given.

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