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

It discloses that no browser is launched, but omits whether it makes network requests, has side effects, requires authentication, or has limits. Since no annotations are provided, the description carries the burden and leaves these operational traits undisclosed; the schema's 'discarded' remarks are not part of the 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 a single compact sentence with no fluff, and the schema is well-structured with additionalProperties false. It loses a point because the brevity comes at the expense of essential context, but the structure itself is clean.

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 optional parameters, no required fields, no output schema, and no annotations, the description is far too sparse for an agent to know how to invoke the tool correctly. It doesn't specify the return value, success/failure criteria, error handling, or which parameter to use, making it incomplete for any real use.

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 descriptions cover all parameters (100%), so the baseline is 3, but the tool-level description doesn't connect them to the stated purpose, and the parameter descriptions are inconsistent with it (e.g., URL is described as 'to normalize or cite,' not to check openability). This leaves an agent unsure which parameter is the intended 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 states a clear action ('check whether a URL can be opened') and a constraint ('no browser is launched'), but the schema exposes 9 unrelated optional parameters (ref, city, feed, json, path, zone, query) whose descriptions reference other operations, making the actual purpose ambiguous and inconsistent with the stated one.

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 about when to use this tool over siblings like playwright-url-ok, fetch-status, or web-fetch. It doesn't specify what 'opened' means, which parameter is relevant, or how to handle failures. The only hint is 'No browser is launched,' which is a constraint, not usage direction.

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