browser_tab_open

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 states it opens a new tab, which implies a mutation, but does not mention side effects like focusing the tab, whether the new tab is activated, or whether the browser must already be launched. The return value is described only as 'JSON response from the API,' which is vague and uninformative. The description fails to disclose any behavioral nuances beyond the obvious action.

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 exceptionally concise: a one-line purpose, a clear args section with each parameter on its own line, and a returns line. No redundant information or fluff. It is front-loaded with the action and structured for quick scanning, making it easy for an agent to parse.

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 that an output schema exists, the vague 'JSON response from the API' might be acceptable. However, the description omits important contextual details such as whether the browser must already be running, whether the new tab becomes active, or any error conditions. It does mention the source of serialno, which is a useful prerequisite. Overall, it covers the basics but lacks behavioral context that could prevent incorrect invocation.

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 schema has zero descriptions (0% coverage), so the description must compensate. It does add meaningful context: serialno is explicitly defined as 'The browser device serialno, from list_devices,' which tells the agent where to obtain it. The url parameter is simply 'The URL to open,' which is self-explanatory but still clarifies its role. This exceeds the baseline for a tool with low schema coverage, though it could add more detail about URL format or expected scheme.

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: 'Open a new tab at a URL.' This clearly distinguishes it from sibling tools like browser_navigate (which likely navigates the current tab) or browser_tab_switch. The purpose is unambiguous and directly actionable.

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 provides no guidance on when to use this tool versus alternatives such as browser_navigate, browser_tab_switch, or browser_tabs. It only lists arguments, with a hint that serialno comes from list_devices, but lacks any context about prerequisites or situations where this tool is preferred. The when-to-use information is entirely absent.

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