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

There are no annotations and the description does not disclose return values, side effects, error behavior, or whether the tool performs network requests. The schema's 'discarded after' notes hint at ignored inputs, but this is not explained in the tool 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 very concise and front-loaded with the main purpose. The schema is verbose but not part of the prose description; no wasted sentences appear in the description itself.

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 definition lacks output schema, return value description, usage examples, and edge-case handling. Given the confusing parameter list and sibling tools, the description is not complete enough for an agent to understand expected behavior or results.

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?

Although schema coverage is 100%, many parameter descriptions are unrelated or misleading, such as 'Git ref name' for ref, 'City name' for city, and 'IANA timezone name' for zone. Only url, host, path, and query loosely align with the stated purpose of checking a URL.

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 and object: 'Check whether a URL can be opened' and clarifies that no browser is launched. However, the input schema contains many unrelated parameters (city, feed, json, zone) that obscure the tool's actual purpose.

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 does not indicate when to use this tool versus alternatives like playwright-url-ok, web-fetch, or normalize-url. The only guidance is the negative constraint 'No browser is launched,' which is insufficient for selecting among sibling tools.

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