switch_to_app · Ulanzi MCP: Risk & Policy

WHAT IT DOES

What switch_to_app does on Ulanzi

AI agents invoke switch_to_app to trigger actions in Ulanzi. 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 switch_to_app needs a policy

This tool triggers an external operation on the Ulanzi TC001 Smart Pixel Clock, changing the currently displayed app. It is an action that affects the device's state (display output), making it Execute. The blast radius is low since it only changes what is shown on a small pixel clock display and is easily reversible.

From the tool's definition Switch to a specific app

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

switch_to_app Rate-limited

switch_to_app 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": {
    "switch_to_app": {
      "limits": [
        {
          "counter": "switch_to_app_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 Ulanzi, so you can run agents against it safely.

FAQ

Questions about switch_to_app

What does the switch_to_app tool do? +

Switch to a specific app. It is categorised as a Execute tool in the Ulanzi MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on switch_to_app? +

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

What risk level is switch_to_app? +

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

Can I rate-limit switch_to_app? +

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

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

switch_to_app is provided by the Ulanzi MCP server (jelloeater/ulanzi-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.