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

No annotations are provided, so the description carries the behavioral disclosure burden. It discloses what the tool does NOT do (no browser launch), but it says nothing about network access, read-only behavior, errors, or whether the URL is actually fetched. For a simple checker this is minimally adequate, but it leaves several behavioral questions unanswered.

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 with no filler; the core purpose is first and the important behavioral caveat follows immediately. The wording is front-loaded and each sentence carries meaning.

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 parameters, no annotations, and no output schema, yet the description covers only the basic URL-checking purpose. It does not explain why so many apparently unrelated parameters exist (city, zone, json, query, path, etc.) or how they interact with the URL check, so an agent has to guess at the intended scope of the tool.

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?

Input schema coverage is 100%, and descriptions for all 9 optional parameters are provided, so the structured data already carries the parameter semantics. The tool description contributes nothing extra about the parameters; baseline score of 3 is appropriate.

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?

Description says the tool checks whether a URL can be opened and explicitly notes it does not launch a browser, which distinguishes it from playwright-url-ok in spirit. It is not purely tautological and names a resource and verb. However, it doesn't name any sibling alternative or the exact check method, so an agent still needs to infer how it differs from fetch-status, normalize-url, or playwright-url-ok.

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 'No browser is launched' sentence gives an implicit selection signal: use this for a non-browser check rather than a rendered browser test. But it does not clearly say when to prefer this tool over alternatives, and does not specify any conditions or prerequisites. Usage guidance is inferred rather than explicitly provided.

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