AI agents call browser_close to permanently remove resources in Camoufox — typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
Closing the browser is an irreversible action that destroys the current browser session, including all open tabs, in-memory session data, and any unsaved state. This cannot be undone without restarting and re-establishing the session, making it Destructive. Severity is high because misuse by an AI agent could terminate an active automation session mid-task, losing all accumulated browser state.
From the tool's definition 'Close the browser' — terminates the browser session irreversibly, destroying all open tabs, session state, cookies, and unsaved data
Documented attack patterns abuse exactly the kind of access browser_close gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Camoufox, and nothing reaches the server without passing your rules. This is the rule we recommend for browser_close:
{
"version": "1",
"default": "deny",
"hide": [
"browser_close"
]
}browser_close disappears from the agent's tool list entirely, and any attempt to call it is denied. The rest of the server keeps working.
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Close the browser. It is categorised as a Destructive tool in the Camoufox MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the Camoufox MCP server in PolicyLayer and add a rule for browser_close: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Camoufox. Nothing to install.
browser_close is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.
Yes. Add a rate_limit block to the browser_close rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for browser_close. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
browser_close is provided by the Camoufox MCP server (rlgrpe/camoufox-mcp-python). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Camoufox, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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22 Camoufox tools catalogued and risk-classified — across an index of 43,000+ MCP servers.