left_click · Computer Use Windows MCP: Risk & Policy

WHAT IT DOES

What left_click does on Computer Use Windows

AI agents invoke left_click to trigger actions in Computer Use Windows. 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 left_click needs a policy

A mouse click is an action that executes whatever UI element is at the target coordinates: it can submit forms, confirm dialogs, delete files via UI, navigate browsers, or trigger any application function. The effects are context-dependent and potentially severe, spanning Write, Destructive, or even Financial outcomes depending on what is clicked.

From the tool's definition Left-click at the given coordinates — triggers UI interactions (button presses, link clicks, form submissions) whose effects depend entirely on what is under the cursor at runtime

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

left_click Rate-limited

left_click 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": {
    "left_click": {
      "limits": [
        {
          "counter": "left_click_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 Computer Use Windows, so you can run agents against it safely.

FAQ

Questions about left_click

What does the left_click tool do? +

Left-click at the given coordinates. ${FRONTMOST_GATE_DESC}. It is categorised as a Execute tool in the Computer Use Windows MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on left_click? +

Register the Computer Use Windows MCP server in PolicyLayer and add a rule for left_click: 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 Computer Use Windows. Nothing to install.

What risk level is left_click? +

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

Can I rate-limit left_click? +

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

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

left_click is provided by the Computer Use Windows MCP server (wimi321/windows-computer-use-skill). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.