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

With no annotations, the description carries the full burden of behavioral disclosure. It does disclose that no browser is launched, which is important, but it does not clarify whether a network request is made, what 'opened' means, or what happens to the provided parameters. The schema hints that many values are 'discarded', but the tool description itself omits these details.

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 core purpose is front-loaded, and the important behavioral caveat about not launching a browser is stated directly and efficiently.

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?

Despite the simple phrasing, the tool has nine optional parameters, no output schema, and no description of return values or selection criteria. An agent cannot confidently determine which parameter to pass or what the tool will return. The description is incomplete for the actual complexity of the input schema.

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 coverage is 100%, so the parameter descriptions already document every field. The tool description adds no additional parameter meaning or guidance on which of the many optional fields should be provided. Baseline 3 applies because the schema does the heavy lifting, but the description fails to clarify why parameters like city, feed, json, and path are accepted for a URL-checking tool.

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 function: checking whether a URL can be opened. The added sentence 'No browser is launched' distinguishes it from browser-url-ok and other browser-dependent siblings. However, 'can be opened' is slightly ambiguous about whether this is a syntactic or network-level check.

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 gives no explicit guidance about when to use this tool versus siblings like browser-url-ok, fetch-status, or normalize-url. The 'No browser is launched' line implies a lightweight check, but there is no explanation of the intended use case or when an alternative would be more appropriate.

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