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

With no annotations provided, the description carries the burden of behavioral disclosure. It usefully discloses the key negative behavior that no browser is launched, but does not mention network side effects, the result format, or how the varied input parameters are handled beyond what the schema hints.

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 one tight, front-loaded sentence with no filler. The brevity is a strength, though it does leave some contextual gaps that would push it lower on completeness.

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?

This tool accepts seven loosely related parameters, has no annotations, and no output schema. The description does not explain the purpose of all these parameters, the return value, or how this tool relates to similar siblings, leaving the agent with significant ambiguity.

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?

All seven parameters already have individual descriptions in the input schema, so the schema does most of the work. The tool description itself adds no additional parameter context, which is acceptable given the high schema coverage.

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 verb and resource: 'Check whether a URL can be opened,' and the clarification 'No browser is launched' distinguishes it from browser-launching siblings like playwright-url-ok. It does not explicitly name alternatives, so it stops short of a 5.

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 is a lightweight URL-checking tool rather than a full browser automation tool, giving some usage direction. However, it gives no explicit guidance on when to choose this over fetch-status, normalize-url, or web-fetch.

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