Critical Risk →

browser_close

Close the page

How to control browser_close ↓

What browser_close does on Wuying AgentBay

AI agents call browser_close to permanently remove resources in Wuying AgentBay — typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.

Critical Risk

Why browser_close needs a policy

Closing a browser page destroys its current state, session, and any unsaved data. This action cannot be undone once executed, making it Destructive. The blast radius is medium since it affects only the current browser page/session within the cloud environment, not broader data or systems.

From the tool's definition 'Close the page' — terminates/destroys the current browser page state irreversibly

Documented attack patterns abuse exactly the kind of access browser_close gives an agent:

How to control browser_close

PolicyLayer is an MCP gateway — it sits between your AI agents and Wuying AgentBay, and nothing reaches the server without passing your rules. This is the rule we recommend for browser_close:

policy.json
{
  "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.

  1. Create a free account and register Wuying AgentBay — nothing to install.
  2. Add this policy — paste it, or build it visually.
  3. Point your MCP client (Claude, Cursor, anything) at your gateway URL.
RESTRICT THIS TOOL →

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Related tools and policies

Go deeper

Questions about browser_close

What does the browser_close tool do? +

Close the page. It is categorised as a Destructive tool in the Wuying AgentBay MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.

How do I enforce a policy on browser_close? +

Register the Wuying AgentBay 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 Wuying AgentBay. Nothing to install.

What risk level is browser_close? +

browser_close is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.

Can I rate-limit browser_close? +

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.

How do I block browser_close completely? +

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.

What MCP server provides browser_close? +

browser_close is provided by the Wuying AgentBay MCP server (michael98671/agentbay). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Wuying AgentBay tool call.

Start from Wuying AgentBay, 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.

59 Wuying AgentBay tools catalogued and risk-classified — across an index of 43,000+ MCP servers.

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