create_tab · Iterm2 MCP: Risk & Policy

WHAT IT DOES

What create_tab does on Iterm2

AI agents invoke create_tab to trigger actions in Iterm2. 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 create_tab needs a policy

Creating a tab in a terminal emulator initiates a new terminal session, which is an external operation with side effects. While the tab creation itself is relatively benign, it opens a new shell session that could be used to execute commands.

From the tool's definition Create a new tab in a window — part of a server that provides 'full control over iTerm2 terminal sessions' and enables users to 'run commands'

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_tab Rate-limited

create_tab 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": {
    "create_tab": {
      "limits": [
        {
          "counter": "create_tab_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 Iterm2, so you can run agents against it safely.

FAQ

Questions about create_tab

What does the create_tab tool do? +

Create a new tab in a window. It is categorised as a Execute tool in the Iterm2 MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on create_tab? +

Register the Iterm2 MCP server in PolicyLayer and add a rule for create_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 Iterm2. Nothing to install.

What risk level is create_tab? +

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

Can I rate-limit create_tab? +

Yes. Add a rate_limit block to the create_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 create_tab completely? +

Set action: deny in the PolicyLayer policy for create_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 create_tab? +

create_tab is provided by the Iterm2 MCP server (lorencarvalho/iterm2-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.