keyboard_key_up · Macinput MCP: Risk & Policy

WHAT IT DOES

What keyboard_key_up does on Macinput

AI agents invoke keyboard_key_up to trigger actions in Macinput. 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 keyboard_key_up needs a policy

Releasing a held key is a desktop GUI execution primitive. It directly triggers OS-level input events that can complete keyboard shortcuts or keypresses, causing application-level side effects. Paired with keyboard_key_down, it forms arbitrary keystroke injection.

From the tool's definition Release a key previously pressed down — part of low-level keyboard input control for desktop GUI automation

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

keyboard_key_up Rate-limited

keyboard_key_up 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": {
    "keyboard_key_up": {
      "limits": [
        {
          "counter": "keyboard_key_up_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 Macinput, so you can run agents against it safely.

FAQ

Questions about keyboard_key_up

What does the keyboard_key_up tool do? +

Release a key previously pressed down. It is categorised as a Execute tool in the Macinput MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on keyboard_key_up? +

Register the Macinput MCP server in PolicyLayer and add a rule for keyboard_key_up: 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 Macinput. Nothing to install.

What risk level is keyboard_key_up? +

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

Can I rate-limit keyboard_key_up? +

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

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

keyboard_key_up is provided by the Macinput MCP server (sigma711/macinput). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.