browser_close_tab

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

No annotations are provided, so the description carries the full burden of behavioral disclosure, yet it says nothing beyond the action. It does not state whether closing is undoable, what happens when the last tab is closed (does the window close?), or whether the page loses state.

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 single short sentence is front-loaded and has zero waste. It is arguably over-compressed, but there is no filler or buried information.

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 destructive, unannotated operation the description is too thin: it omits default behavior when no parameters are supplied, edge cases like the last tab, and side effects. The schema covers the parameters, but the behavioral picture an agent needs before closing a tab is missing.

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% and both optional parameters (tabId, windowId, with their defaulting behavior) are fully documented in the schema. The description adds no additional meaning, so the baseline 3 applies.

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?

"Close a tab" names a specific verb and resource, so the basic action is clear. However, with siblings browser_close_window and browser_close_popup_bubble in the set, it offers no differentiation about what a "tab" is versus a window or popup bubble, leaving the agent to infer scope.

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?

There is no guidance on when to use this versus browser_close_window, browser_close_popup_bubble, or browser_batch. Usage is only implied by the verb; no prerequisites, exclusions, or alternative routing are stated.

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