close_session · Iterm2 MCP: Risk & Policy

WHAT IT DOES

What close_session does on Iterm2

AI agents use close_session to create or update resources in Iterm2 — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Iterm2 environment.

WHY IT NEEDS A POLICY

Why close_session needs a policy

An AI agent can call close_session faster than any human can review — one bad instruction and it creates or modifies resources in Iterm2 by the hundred, each call as confident as the last.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

close_session Rate-limited

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

FAQ

Questions about close_session

What does the close_session tool do? +

Close a specific session. It is categorised as a Write tool in the Iterm2 MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on close_session? +

Register the Iterm2 MCP server in PolicyLayer and add a rule for close_session: 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 close_session? +

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

Can I rate-limit close_session? +

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

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

close_session 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.