assert_state · React Native MCP: Risk & Policy

WHAT IT DOES

What assert_state does on React Native

AI agents use assert_state 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 assert_state needs a policy

An AI agent can call assert_state faster than any human can review — one bad instruction and it creates or modifies resources in React Native by the hundred, each call as confident as the last.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

assert_state Rate-limited

assert_state 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": {
    "assert_state": {
      "limits": [
        {
          "counter": "assert_state_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 assert_state

What does the assert_state tool do? +

Assert React state hook value matches expected. Use with selector and hookIndex. 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 assert_state? +

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

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

Can I rate-limit assert_state? +

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

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

assert_state 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.