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

With no annotations provided, the description carries the full burden, but it only discloses that no browser is launched. It does not say whether the tool performs a network request, what the check involves, whether it has side effects, or what constraints exist (e.g., timeouts, access). The added note is useful but leaves most behavioral expectations undefined.

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 wasted words, and the key fact ('No browser is launched') is placed as a meaningful second sentence. It is terse, but a bit sparse for the tool's complexity, so it loses one point for context rather than content.

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 9 parameters, no required fields, and no output schema, the description is far too brief. It only mentions 'url', ignoring all other parameter categories, and does not describe what the tool returns or how the check is performed. An agent would need to infer most context beyond the schema, making this incomplete.

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?

The input schema covers 100% of the parameters with descriptions, so the baseline is 3. The tool description adds no parameter-level meaning and does not clarify how the many optional parameters relate to the purpose or each other; it simply relies on the schema, which is adequate but not enhanced.

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 action ('check whether a URL can be opened') with a clarifying behavioral note ('No browser is launched'). However, 'can be opened' is ambiguous (HTTP success vs. URL validity vs. renderability), and the tool's input schema contains many parameters unrelated to URLs (ref, city, json, path, zone), which the description does not reconcile. It is clear enough to be useful but not enough to fully disambiguate from 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 explicit guidance about when to use this tool instead of alternatives like browser-url-ok, fetch-status, or normalize-url. The statement 'No browser is launched' hints at a lightweight alternative to a browser-based check, but it never names the alternative or the conditions that should drive the choice.

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