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

With no annotations present, the description carries the full burden of behavioral disclosure. It reveals that no browser is launched, which is a useful distinguishing trait, but it omits whether a network request is made, whether the operation is read-only, or what the result actually indicates about the URL.

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 the main verb and resource front-loaded. The second sentence adds a critical exclusion without any wasted words. It is appropriately sized for the 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?

Despite a small tool description, the tool has seven parameters with mixed relevance, no output schema, and no description of return values. An agent would not understand why unrelated parameters are accepted or what the expected response is. The minimal description leaves significant gaps in invoking the tool correctly.

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 have individual descriptions in the input schema, so the schema already provides comprehensive coverage. The tool description adds no extra meaning about how parameters relate to the URL check or why unrelated-looking fields like city, feed, and json are accepted.

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 clear action (check whether a URL can be opened) and distinguishes itself from browser-based tools with 'No browser is launched.' It does not explicitly name sibling tools or clarify what 'can be opened' means in terms of HTTP status or reachability, which leaves some ambiguity.

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 on when to use this tool over alternatives like browser-url-ok, fetch-status, or web-fetch. The phrase 'No browser is launched' implies a lightweight use case but stops short of explaining trade-offs or exclusion criteria.

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