browser_close_tab

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

With no annotations, the description carries the full burden. It discloses a key side effect: 'The tab's binding is automatically removed.' However, it does not state whether the operation is reversible, what happens if the tabId is invalid or not bound, or any permissions needed. The destructive nature is implied by 'close' but not elaborated.

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 extremely concise—two short sentences with no filler. It front-loads the primary action ('Close a browser tab') and then provides a single important side effect. Every word earns its place.

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 simple one-parameter tool with no output schema, the description is largely adequate. It covers the main purpose, the binding prerequisite, and a key side effect. It does not detail error handling or return values, but given the simplicity and the absence of an output schema, this is sufficient. Sibling tools like browser_list_tabs can provide tabId details.

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?

Although the schema already describes tabId as 'Tab ID to close' (100% coverage), the description adds semantic value by clarifying that the tab must be 'previously bound to this agent.' This goes beyond the schema's definition and helps the agent select the correct tab.

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 function: 'Close a browser tab previously bound to this agent.' It uses a specific verb ('close') and resource ('browser tab') and adds a crucial constraint ('previously bound'), distinguishing it from siblings like browser_open_tab or browser_set_active_tab.

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 implies when to use it (to close a bound tab) but does not explicitly provide when-not-to-use scenarios or alternatives. It does not mention that tabId can be obtained via browser_list_tabs, though this is a reasonable inference. No exclusions or alternative tool references are given, leaving usage guidance implicit.

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