AI agents call close-browser to permanently remove resources in WDIO MCP Server — typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
Closing a browser session is an irreversible action that destroys the active session context. Any unsaved data, session tokens, or in-progress automation state cannot be recovered. This fits the Destructive category as the session cannot be undone once terminated.
From the tool's definition 'Close the active browser session' — terminates the browser session irreversibly, destroying any unsaved state, open pages, and session data.
Documented attack patterns abuse exactly the kind of access close-browser gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and WDIO MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for close-browser:
{
"version": "1",
"default": "deny",
"hide": [
"close-browser"
]
}close-browser 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 active browser session. It is categorised as a Destructive tool in the WDIO MCP Server MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the WDIO MCP Server MCP server in PolicyLayer and add a rule for close-browser: 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 WDIO MCP Server. Nothing to install.
close-browser 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 close-browser 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 close-browser. 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.
close-browser is provided by the WDIO MCP Server MCP server (siri100/wdio-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from WDIO MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
7 WDIO MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.