Close a browser tab directly, with an optional target to close a specific tab instead of the active one.
Close a tab. Without target, closes the active tab.
This tool declares no required parameters. Add optional parameters from the input schema as needed.
{
"id": 1,
"jsonrpc": "2.0",
"method": "tools/call",
"params": {
"arguments": {},
"name": "browser_close_tab"
}
}| Name | Required | Description | Default |
|---|---|---|---|
| target | No |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are present, so the description carries the full burden. It discloses the destructive action and the active-tab default, but it does not explain whether closing is reversible, what happens if it is the last tab, or what response the tool returns.
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?
Two short sentences with no filler. The main action and the default behavior are stated directly and concisely, with the most important conditional behavior front-loaded.
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?
The default invocation is fully described and the operation is simple. However, for non-default usage with a target, the agent is left guessing about the target value's format, and with no output schema there is no stated expectation of return behavior.
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?
With 0% schema coverage for target, the description must compensate. It adds meaning by explaining the null case ('closes the active tab'), but it does not define what a string target value should be or where to obtain it, such as a tab ID.
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?
States the exact verb and resource: 'Close a tab.' It immediately clarifies the default behavior ('Without target, closes the active tab'), which also distinguishes it from tab-creation and navigation siblings like browser_new_tab and browser_switch_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?
Provides clear invocation context by explaining what happens when target is omitted. It does not explicitly name alternatives or when-not-to-use conditions, but the intended usage is unambiguous for this simple operation.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.