tmux_select_pane · Tmux MCP: Risk & Policy

WHAT IT DOES

What tmux_select_pane does on Tmux

AI agents invoke tmux_select_pane to trigger actions in Tmux. 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 tmux_select_pane needs a policy

Selecting/focusing a pane is a UI state change that triggers an external operation on the tmux session. While it doesn't run code directly, it changes the active pane context which can affect subsequent commands sent to the session. The blast radius is low since it's just changing focus, but it does interact with an external process (tmux) in a way that goes beyond a pure read.

From the tool's definition Select/focus a specific tmux pane

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

tmux_select_pane Rate-limited

tmux_select_pane 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": {
    "tmux_select_pane": {
      "limits": [
        {
          "counter": "tmux_select_pane_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 Tmux, so you can run agents against it safely.

FAQ

Questions about tmux_select_pane

What does the tmux_select_pane tool do? +

Select/focus a specific tmux pane. It is categorised as a Execute tool in the Tmux MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on tmux_select_pane? +

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

What risk level is tmux_select_pane? +

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

Can I rate-limit tmux_select_pane? +

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

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

tmux_select_pane is provided by the Tmux MCP server (wenlixiao-cs/tmux-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.