// MCP TOOL REFERENCE

focus_window

ServermacOS Simulator MCP Server
CategoryExecute

WHAT IT DOES

What focus_window does on macOS Simulator MCP Server

AI agents invoke focus_window to trigger actions in macOS Simulator 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.

THE RISK

High Risk

Why focus_window needs a policy

This tool triggers an external OS-level operation (window focus/activation) that changes system state and redirects input to a specific application. It is not merely reading data, but actively manipulating the windowing environment.

From the tool's definition 'Bring a specific window to the foreground and make it the active/focused window' and 'Essential for directing keyboard and mouse input to the correct application'

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

POLICY

How to control focus_window

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

policy.json

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

focus_window 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.

Create a free account and register macOS Simulator 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.

RATE-LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More macOS Simulator MCP Server tools

Destructive cleanup_screenshots Clean up old screenshots from temporary folder Execute wait Pause execution for a specified duration in milliseconds to allow time for UI updates, ani Execute wait_for_element Wait for specific text or UI element to appear on screen before continuing. Essential for Execute hover Hover the mouse over specific coordinates for a duration. Useful for triggering tooltips, Execute click Perform mouse clicks at precise screen coordinates with support for left, right, or middle Execute key_press Execute keyboard shortcuts and special key combinations essential for system navigation an Execute mouse_move Move the mouse cursor to precise screen coordinates without clicking. Useful for hover act Execute right_click Right-click at specific coordinates to open context menus. Equivalent to click with button

All 28 macOS Simulator MCP Server tools →

Execute tools on other servers

Android Forensics ADB MCP Server adb_shell_command EMBA-MCP run_emba_scan Frida Game Hacking MCP remove_breakpoint Procmon request_elevation

Go deeper

High-risk tools in macOS Simulator MCP Server → Every high-risk tool this server exposes, in one view.
All high-risk MCP tools → Every high-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.
Agent sandbox → Bounding what an agent can execute and where the boundary should sit.
Least privilege for MCP → Granting agents the minimum tool surface the task needs.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about focus_window

What does the focus_window tool do? +

Bring a specific window to the foreground and make it the active/focused window using partial title matching. Essential for directing keyboard and mouse input to the correct application. Supports flexible partial matching - you don. It is categorised as a Execute tool in the macOS Simulator 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 focus_window? +

Register the macOS Simulator MCP Server MCP server in PolicyLayer and add a rule for focus_window: 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 macOS Simulator MCP Server. Nothing to install.

What risk level is focus_window? +

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

Can I rate-limit focus_window? +

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

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

focus_window is provided by the macOS Simulator MCP Server MCP server (ohqay/mac-commander). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every macOS Simulator MCP Server tool call.

Start from macOS Simulator 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 →

Free to start. No card required.

28 macOS Simulator MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.