switch_keyboard · React Native MCP: Risk & Policy

WHAT IT DOES

What switch_keyboard does on React Native

AI agents invoke switch_keyboard to trigger actions in React Native. 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_keyboard needs a policy

This tool triggers an external operation on a simulator/emulator by changing the keyboard language setting. It modifies system/device state (keyboard layout) and has side effects that affect subsequent actions. It's not a simple read, and while the change may be reversible, it's an execution of a device-level action rather than a data write, placing it in the Execute category.

From the tool's definition Switch keyboard language on simulator/emulator. Use before input_text for correct layout.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

switch_keyboard Rate-limited

switch_keyboard 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_keyboard": {
      "limits": [
        {
          "counter": "switch_keyboard_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 React Native, so you can run agents against it safely.

FAQ

Questions about switch_keyboard

What does the switch_keyboard tool do? +

Switch keyboard language on simulator/emulator. Use before input_text for correct layout. It is categorised as a Execute tool in the React Native 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_keyboard? +

Register the React Native MCP server in PolicyLayer and add a rule for switch_keyboard: 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 React Native. Nothing to install.

What risk level is switch_keyboard? +

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

Can I rate-limit switch_keyboard? +

Yes. Add a rate_limit block to the switch_keyboard 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_keyboard completely? +

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

switch_keyboard is provided by the React Native MCP server (@ohah/react-native-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.