lock_screen · Windows MCP Server MCP: Risk & Policy

WHAT IT DOES

What lock_screen does on Windows MCP Server

AI agents invoke lock_screen to trigger actions in Windows MCP Server. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why lock_screen needs a policy

Locking the workstation is an irreversible immediate system action (until a user unlocks it) that triggers an external OS-level operation. It does not delete data, but it disrupts user sessions and could deny access, placing it in Execute. It is not Destructive because the action is reversible by logging back in.

From the tool's definition 'Lock the workstation' — triggers a system-level OS operation that locks the Windows session

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

lock_screen Rate-limited

lock_screen stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "lock_screen": {
      "limits": [
        {
          "counter": "lock_screen_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Windows MCP Server, so you can run agents against it safely.

FAQ

Questions about lock_screen

What does the lock_screen tool do? +

Lock the workstation. It is categorised as a Execute tool in the Windows MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on lock_screen? +

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

What risk level is lock_screen? +

lock_screen is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit lock_screen? +

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

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

lock_screen is provided by the Windows MCP Server MCP server (romeo2badboy-rgb/windows-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.