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

With no annotations provided, the description carries the full burden of behavioral disclosure. It does disclose that no browser is launched, which is useful, but it doesn't say whether a network request occurs, whether any state changes or data is discarded, or what kind of response is returned. The brief description leaves major behavioral unknowns for a URL-checking tool.

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 extremely short and front-loaded: 'Check whether a URL can be opened. No browser is launched.' Both sentences are meaningful and there is no filler. However, the brevity comes at the cost of important behavioral and selection context, so it is not fully 'appropriately sized' for a tool with 9 parameters and no annotations.

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?

Given the complexity of 9 optional parameters, no annotations, and no output schema, the description is too sparse. It doesn't explain what the tool returns, which parameters are relevant to the URL check, or whether the check is a network request. 'No browser is launched' is the only contextual clue, which is insufficient for a no-annotation tool.

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 provides descriptions for all 9 parameters, so the 100% schema coverage sets a baseline of 3. The tool description itself adds no parameter-level meaning and does not explain how the many unrelated-looking parameters relate to 'checking whether a URL can be opened.' Still, the schema already describes each parameter clearly, so this is not a critical gap.

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 added sentence 'No browser is launched' clarifies the operation's nature and helps differentiate it from browser-url-ok. However, it doesn't explicitly name an alternative or describe the underlying check mechanism, so it falls short of full sibling differentiation.

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 web-fetch. 'No browser is launched' hints that this is not a browser-rendering check, but it does not state selection criteria or mention alternatives. An agent must infer usage context from the tool name and the negative statement.

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