cmux_rename_tab · Cmux MCP: Risk & Policy

WHAT IT DOES

What cmux_rename_tab does on Cmux

AI agents use cmux_rename_tab to create or update resources in Cmux — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Cmux environment.

WHY IT NEEDS A POLICY

Why cmux_rename_tab needs a policy

Renaming a tab modifies metadata (the tab's name/title) in a reversible way. This is a Write operation with low blast radius since it only changes a display label. Confidence is moderate because the description 'Set a tab' is uninformative and truncated, leaving some ambiguity about what exactly is being set.

From the tool's definition Tool name 'cmux_rename_tab' and description 'Set a tab' — suggests renaming/setting a tab label or title

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

cmux_rename_tab Rate-limited

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

FAQ

Questions about cmux_rename_tab

What does the cmux_rename_tab tool do? +

Set a tab. It is categorised as a Write tool in the Cmux MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on cmux_rename_tab? +

Register the Cmux MCP server in PolicyLayer and add a rule for cmux_rename_tab: 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_rename_tab? +

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

Can I rate-limit cmux_rename_tab? +

Yes. Add a rate_limit block to the cmux_rename_tab 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_rename_tab completely? +

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

cmux_rename_tab 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.