Close the active browser window to end the current session and release resources.
Close the MCP's browser window.
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"
}
}| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
v0.2.3Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description must carry the full behavioral burden. It states the action but does not disclose whether closing the window destroys session state, whether the operation is idempotent, or what happens if no browser window is open.
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 a single seven-word sentence with no filler, and it leads directly with the action verb and target. Every word earns its place for such a simple tool.
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 zero-parameter, no-output-schema close operation, the description captures the essential operational meaning: what the tool does and what it acts on. Minor gaps such as edge-case behavior when no browser is open or return-value details would be helpful but are not critical at this level of complexity.
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 tool has zero parameters and the input schema is complete, so there is no parameter surface requiring extra documentation. The description correctly avoids inventing parameter details that do not exist.
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 uses a specific verb ('close') and identifies a distinct resource ('the MCP's browser window'), clearly distinguishing it from browser_* siblings that open, push, pull, readback, screenshot, or send keys. There is no ambiguity about what action this tool performs.
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 intended usage is implied: use this when you want to close the MCP's browser window. However, the description gives no explicit guidance about preconditions, when not to use it, or relationships to alternatives like browser_open.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.