close_browser_session

THE RISK

Critical Risk

Why close_browser_session needs a policy

This tool irreversibly terminates a browser session and destroys all associated resources (browser instance, pages, context). Any unsaved state or work in progress within that session is permanently lost. This is not merely a write operation — it is a destructive cleanup that cannot be undone, matching the Destructive category.

From the tool's definition Close a specific browser session and cleanup all resources including browser instance, pages, and context.

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

POLICY

How to control close_browser_session

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

policy.json

{
  "version": "1",
  "default": "deny",
  "hide": [
    "close_browser_session"
  ]
}

close_browser_session disappears from the agent's tool list entirely, and any attempt to call it is denied. The rest of the server keeps working.

Create a free account and register RunAutomation MCP Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

RESTRICT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More RunAutomation MCP Server tools

Destructive clear_codegen_session Clear a code generation session without generating a test Destructive cleanup_idle_sessions Automatically close idle browser sessions that haven Destructive playwright_close Close the browser and release all resources Execute playwright_delete Perform an HTTP DELETE request Execute playwright_batch_ai_visual_compare Run batch AI visual comparisons across multiple pages Execute playwright_emulate_device Emulate a mobile device with specific viewport, user agent, and capabilities. Supports all Execute playwright_evaluate Execute JavaScript in the browser console Execute playwright_expect_response Ask Playwright to start waiting for a HTTP response. This tool initiates the wait operatio

All 91 RunAutomation MCP Server tools →

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Go deeper

Critical-risk tools in RunAutomation MCP Server → Every critical-risk tool this server exposes, in one view.
All critical-risk MCP tools → Every critical-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Blast radius → How much damage one compromised or confused agent can do — and how to bound it.
Tool call approval → Approval gates on individual tool calls: auto-allow, prompt, or deny.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about close_browser_session

What does the close_browser_session tool do? +

Close a specific browser session and cleanup all resources including browser instance, pages, and context. It is categorised as a Destructive tool in the RunAutomation MCP Server 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 close_browser_session? +

Register the RunAutomation MCP Server MCP server in PolicyLayer and add a rule for close_browser_session: 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 RunAutomation MCP Server. Nothing to install.

What risk level is close_browser_session? +

close_browser_session 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 close_browser_session? +

Yes. Add a rate_limit block to the close_browser_session 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 close_browser_session completely? +

Set action: deny in the PolicyLayer policy for close_browser_session. 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 close_browser_session? +

close_browser_session is provided by the RunAutomation MCP Server MCP server (tayyabakmal1/runautomation-mcpserver). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every RunAutomation MCP Server tool call.

Start from RunAutomation MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →