browser_open_tab

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 discloses key side effects: the tab is bound to the agent, set as the active tab, and optionally navigates to a URL. It also explains the label's role in subsequent calls. While it doesn't cover edge cases like invalid URLs or tab management on agent termination, it provides substantial transparency for a simple open-tab operation.

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 concise and well-structured, consisting of two sentences that front-load the core purpose. Every sentence adds value: the first defines the action, and the second explains parameters and the active-tab side effect. No fluff or redundancy.

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?

For a tool with two optional parameters and no output schema, the description covers the essential aspects: what it does, how parameters behave, and immediate side effects. It could explicitly state what happens when no URL is provided (e.g., opens a blank tab), but this is implied. The description is adequate for an agent to select and invoke 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?

Schema coverage is 100%: both 'url' and 'label' have detailed descriptions in the schema. The tool description adds some context beyond the schema, such as the label being used by the LLM to refer to the tab in subsequent calls, and the URL navigating after open. However, this is minor additional meaning; the schema already does the heavy lifting.

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 clearly states the tool's action: 'Open a new browser tab and bind it to this agent.' It specifies the resource (browser tab) and the binding behavior, which distinguishes it from sibling tools like browser_close_tab or browser_navigate. The additional note about setting the tab as active further clarifies its unique role.

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 clear context for when to use this tool: when a new tab needs to be opened and bound to the agent. It explains optional URL and label parameters, implying use cases. However, it does not explicitly name alternatives or state when not to use it (e.g., when an existing tab should be navigated instead).

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