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

With no annotations provided, the description has the full burden of disclosing behavior. It only discloses that no browser is launched; it does not explain what 'opened' means, whether a network request is made, what side effects or rate limits exist, or what the return value indicates. The schema mentions that several parameters are 'discarded,' but the description itself adds little behavioral transparency.

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 wasted words. The main action is front-loaded, and the clarifying no-browser statement earns its place.

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 no output schema and no annotations, so the description must compensate. It does not explain what the tool returns (e.g., boolean, status, details) or how the URL check is performed. The gap between the URL-focused description and the 9-parameter schema with discarding behavior is left entirely unexplained, making the description insufficient for reliable invocation.

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%, so the baseline is 3. The description adds no parameter-specific information, but the schema already documents each parameter's meaning and discard behavior. This is acceptable given the high coverage.

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 and resource: 'Check whether a URL can be opened.' The second sentence, 'No browser is launched,' gives a useful distinction from browser-based tools. However, 'can be opened' is slightly ambiguous—it could mean reachable, valid, or renderable—and the description does not account for the many unrelated parameters in the schema.

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 description implies a clear use case: checking URL openability without launching a browser. It offers an implicit exclusion of browser-dependent checks, but it never names alternatives such as browser-url-ok or states explicit when-to-use/when-not-to-use conditions.

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