computer_key · Computer Use MCP Server MCP: Risk & Policy

WHAT IT DOES

What computer_key does on Computer Use MCP Server

AI agents invoke computer_key to trigger actions in Computer Use 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 computer_key needs a policy

This tool simulates keyboard input at the OS level via xdotool, triggering arbitrary key presses and combinations on a live desktop. An AI agent could misuse this to execute system commands (e.g., opening terminals, triggering shortcuts like Alt+F4, Ctrl+Alt+T), delete files, or interact with any focused application in unintended ways.

From the tool's definition Press a key or key combination. Use xdotool key names

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

computer_key Rate-limited

computer_key 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": {
    "computer_key": {
      "limits": [
        {
          "counter": "computer_key_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 MCP Server, so you can run agents against it safely.

FAQ

Questions about computer_key

What does the computer_key tool do? +

Press a key or key combination. Use xdotool key names:. It is categorised as a Execute tool in the Computer Use 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 computer_key? +

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

What risk level is computer_key? +

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

Can I rate-limit computer_key? +

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

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

computer_key is provided by the Computer Use MCP Server MCP server (sebastianbaltes/claude_code_computer_use_mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.