type_text · React Native MCP: Risk & Policy

WHAT IT DOES

What type_text does on React Native

AI agents use type_text to create or update resources in React Native — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your React Native environment.

WHY IT NEEDS A POLICY

Why type_text needs a policy

This is a Write operation because it creates or modifies data in a reversible manner—typing text into input fields can be undone (cleared, edited). It does not execute arbitrary code (Execute), delete data (Destructive), nor move money (Financial).

From the tool's definition Tool performs 'Type text into TextInput' which modifies app state by writing user input to text fields. While it writes to UI components rather than data structures, the act of inputting text constitutes reversible modification of application state.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

type_text Rate-limited

type_text stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "type_text": {
      "limits": [
        {
          "counter": "type_text_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

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 type_text

What does the type_text tool do? +

Type text into TextInput by uid (from query_selector). Supports Unicode. Use instead of input_text for non-ASCII. It is categorised as a Write tool in the React Native MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on type_text? +

Register the React Native MCP server in PolicyLayer and add a rule for type_text: 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 type_text? +

type_text is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit type_text? +

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

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

type_text 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.