toggle_error · React Devtools MCP: Risk & Policy

WHAT IT DOES

What toggle_error does on React Devtools

AI agents invoke toggle_error to trigger actions in React Devtools. 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 toggle_error needs a policy

This tool triggers a state change in a React application by toggling error boundary state, which is an external operation that affects the running application's behavior. It is not purely reading data, nor is it creating/modifying persistent data in a reversible write sense — it executes a behavioral change in the app under inspection. Misuse could cause application errors or mask real error states during testing.

From the tool's definition Toggle error boundary state for testing

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

toggle_error Rate-limited

toggle_error 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": {
    "toggle_error": {
      "limits": [
        {
          "counter": "toggle_error_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 Devtools, so you can run agents against it safely.

FAQ

Questions about toggle_error

What does the toggle_error tool do? +

Toggle error boundary state for testing. It is categorised as a Execute tool in the React Devtools MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on toggle_error? +

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

What risk level is toggle_error? +

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

Can I rate-limit toggle_error? +

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

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

toggle_error is provided by the React Devtools MCP server (skylarbarrera/react-devtools-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.