cmux_wait_ready · Cmux MCP: Risk & Policy

WHAT IT DOES

What cmux_wait_ready does on Cmux

AI agents invoke cmux_wait_ready to trigger actions in Cmux. 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 cmux_wait_ready needs a policy

cmux_wait_ready performs polling and state-dependent triggering on a terminal/browser UI. While it appears non-destructive on its surface, it executes a wait-loop that blocks until readiness criteria are satisfied, then returns results. This is fundamentally an execution operation (polling loop, conditional branching) rather than passive data retrieval.

From the tool's definition Tool polls a surface/panel and waits for readiness state, which involves monitoring and triggering on screen state changes.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

cmux_wait_ready Rate-limited

cmux_wait_ready 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": {
    "cmux_wait_ready": {
      "limits": [
        {
          "counter": "cmux_wait_ready_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 Cmux, so you can run agents against it safely.

FAQ

Questions about cmux_wait_ready

What does the cmux_wait_ready tool do? +

Poll a surface/panel until it looks ready for input, then return the final screen. Ready = the screen matches. It is categorised as a Execute tool in the Cmux MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on cmux_wait_ready? +

Register the Cmux MCP server in PolicyLayer and add a rule for cmux_wait_ready: 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 Cmux. Nothing to install.

What risk level is cmux_wait_ready? +

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

Can I rate-limit cmux_wait_ready? +

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

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

cmux_wait_ready is provided by the Cmux MCP server (puchkoff/cmux-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.