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

No annotations are provided, so the description carries the full burden. It discloses 'No browser is launched,' which is useful, but it does not cover return format, network access, timeouts, failure modes, or how the many 'discarded' parameters affect behavior. This is a significant atax for a tool with no annotation safety profile.

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?

Two short sentences, no fluff, front-loaded with the core action. The statement 'No browser is launched' earns its place by dispelling a likely expectation for a Playwright-related tool. It could offer more detail, but the conciseness dimension rewards efficiency.

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 9 optional parameters, no output schema, and no annotations, yet the description is minimal. The schema describes each parameter, but names like 'ref', 'city', 'zone', and 'query' suggest a broader shape-check capability that the description does not reconcile. An agent cannot confidently determine what parameters actually matter or what the return value looks like.

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 description coverage is 100%, and each of the 9 parameters has its own description. The tool description itself adds no parameter-level meaning beyond the schema, so the baseline of 3 applies.

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 specific verb and resource: 'Check whether a URL can be opened' and adds a meaningful caveat, 'No browser is launched.' This is clear for a URL-checking tool, though it does not explicitly differentiate from sibling tools like browser-url-ok beyond the no-browser trait.

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?

No guidance on when to use this tool versus alternatives. It does not name sibling tools, specify when to use it instead of a fetch or browser-launching tool, or mention any exclusions. The agent must infer usage from the name and one-line description.

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