send_control_character · Iterm2 MCP: Risk & Policy

WHAT IT DOES

What send_control_character does on Iterm2

AI agents invoke send_control_character 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 send_control_character needs a policy

Sending control characters to a terminal session (e.g., Ctrl+C, Ctrl+D, Ctrl+Z) can interrupt processes, close sessions, send EOF signals, or trigger other terminal-level actions. On a server with full iTerm2 control, this falls under Execute since it triggers external operations in the terminal.

From the tool's definition Tool name 'send_control_character' on a server providing 'full control over iTerm2 terminal sessions' that can 'run commands' and 'interact with terminal sessions'

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

send_control_character Rate-limited

send_control_character 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": {
    "send_control_character": {
      "limits": [
        {
          "counter": "send_control_character_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 send_control_character

What does the send_control_character tool do? +

send_control_character. 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 send_control_character? +

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

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

Can I rate-limit send_control_character? +

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

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

send_control_character 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.