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 reveals one behavior (no browser launch) but fails to clarify whether the tool makes a network request, performs a purely local shape check, or returns a boolean vs. a detailed result. The schema's 'discarded after the shape check' hints at a shape-validation behavior, but the description omits this crucial distinction.

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, front-loaded sentence that conveys its primary action efficiently with no wasted words. It is appropriately concise for a simple tool, though it sacrifices detail needed for the tool's apparent parameter complexity.

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 no annotations, no output schema, and seven parameters, this description is incomplete. It does not define what 'can be opened' means (network reachability vs. syntactic validity), what the return value is, or how the non-URL parameters are handled. An agent would not know how to interpret results or distinguish this from related fetch/check tools.

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 seven parameters, so schema coverage is complete. The description adds no parameter-specific meaning; it references only 'a URL' while the schema includes many unrelated inputs, and it does not explain how or why those other parameters are discarded.

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, 'Check whether a URL can be opened,' and adds 'No browser is launched' to differentiate it from browser-launching siblings like playwright-url-ok. However, it only mentions URLs while the input schema exposes many non-URL parameters (ref, city, feed, json, path), leaving the tool's actual scope ambiguous.

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 phrase 'No browser is launched' implies this tool is appropriate when a lightweight check without browser overhead is desired, but it does not explicitly name alternative tools or state when not to use it. Usage context is only implied, not spelled out.

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