start_render_highlight · React Native MCP: Risk & Policy

WHAT IT DOES

What start_render_highlight does on React Native

AI agents invoke start_render_highlight 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 start_render_highlight needs a policy

This tool triggers external operations on a running device/simulator (enabling visual overlays and instrumentation) whose effects depend on the application state and runtime environment. It is not merely querying data (Read), nor is it creating/modifying application data reversibly (Write), nor is it destructive.

From the tool's definition The tool 'start_render_highlight' performs a runtime action that 'Show visual re-render overlay on device' and 'Highlights re-rendering components', indicating it executes code or commands to modify the UI display state of a React Native application.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

start_render_highlight Rate-limited

start_render_highlight 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": {
    "start_render_highlight": {
      "limits": [
        {
          "counter": "start_render_highlight_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 start_render_highlight

What does the start_render_highlight tool do? +

Show visual re-render overlay on device. Highlights re-rendering components with count badges. 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 start_render_highlight? +

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

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

Can I rate-limit start_render_highlight? +

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

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

start_render_highlight 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.