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

The description discloses that no browser is launched, which is a useful behavioral detail. However, it does not explain what 'opened' means (e.g., HTTP status, URL validity), whether network requests are made, what the return value is, or why multiple unrelated parameters are accepted. The parameter descriptions hint at 'shape checks' and 'discarded' values, further confusing the actual behavior.

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 a single concise sentence with no unnecessary words. The parameter descriptions are also brief and follow a consistent pattern, making the schema easy to scan.

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?

With no output schema and no mention of the return type or format, an agent cannot know what result to expect from the tool. The description also fails to explain the relationship between the tool's purpose and the large set of optional parameters, leaving the overall behavior under-specified.

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?

Each parameter has a description that adds some semantic meaning beyond the raw name and type, but the meanings are inconsistent with the stated purpose of checking URL openness. For example, 'City name for a public weather hint' and 'IANA timezone name' are irrelevant to a URL check, while 'url' is described as 'to normalize or cite' rather than 'to check if open.' The descriptions are present but not well-aligned with the tool's core function.

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 clearly states the tool's action ('Check whether a URL can be opened') and includes a helpful clarification that no browser is launched. However, the presence of many seemingly unrelated parameters (city, zone, query, etc.) introduces ambiguity about the actual scope of the tool.

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 is provided on when to use this tool versus related siblings such as fetch-status, normalize-url, or web-fetch. The description does not mention alternatives or indicate specific scenarios where this tool is preferred.

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