ui_wait_for_change · UI Bridge MCP: Risk & Policy

WHAT IT DOES

What ui_wait_for_change does on UI Bridge MCP

AI agents invoke ui_wait_for_change to trigger actions in UI Bridge MCP. 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 ui_wait_for_change needs a policy

This tool executes a blocking/waiting operation on external UI state rather than passively reading. While not immediately destructive or financial, it represents an Execute-category action that initiates a real-world process interaction.

From the tool's definition The tool name is 'ui_wait_for_change' and description states 'Wait for the runner'. Given the server's purpose of enabling AI to 'interact with UI elements' and 'control mode for the runner's own UI', this tool triggers an external operation (waiting for UI…

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

ui_wait_for_change Rate-limited

ui_wait_for_change 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": {
    "ui_wait_for_change": {
      "limits": [
        {
          "counter": "ui_wait_for_change_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 UI Bridge MCP, so you can run agents against it safely.

FAQ

Questions about ui_wait_for_change

What does the ui_wait_for_change tool do? +

Wait for the runner. It is categorised as a Execute tool in the UI Bridge MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on ui_wait_for_change? +

Register the UI Bridge MCP server in PolicyLayer and add a rule for ui_wait_for_change: 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 UI Bridge MCP. Nothing to install.

What risk level is ui_wait_for_change? +

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

Can I rate-limit ui_wait_for_change? +

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

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

ui_wait_for_change is provided by the UI Bridge MCP server (qontinui/ui-bridge-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.