terminal-refresh · Mcp Terminal MCP: Risk & Policy

WHAT IT DOES

What terminal-refresh does on Mcp Terminal

AI agents invoke terminal-refresh to trigger actions in Mcp Terminal. 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 terminal-refresh needs a policy

This tool sends a Unix signal (SIGWINCH) to a running process via the PTY. Sending signals to processes is an external operation that can affect process behavior. While SIGWINCH is typically benign (it notifies processes of terminal resize), signal delivery is an Execute-category action — it triggers an external operation on a running process.

From the tool's definition Triggers a redraw of the running program by sending SIGWINCH (resize signal) to the PTY

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

terminal-refresh Rate-limited

terminal-refresh 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": {
    "terminal-refresh": {
      "limits": [
        {
          "counter": "terminal-refresh_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 Mcp Terminal, so you can run agents against it safely.

FAQ

Questions about terminal-refresh

What does the terminal-refresh tool do? +

Triggers a redraw of the running program by sending SIGWINCH (resize signal) to the PTY. It is categorised as a Execute tool in the Mcp Terminal MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on terminal-refresh? +

Register the Mcp Terminal MCP server in PolicyLayer and add a rule for terminal-refresh: 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 Mcp Terminal. Nothing to install.

What risk level is terminal-refresh? +

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

Can I rate-limit terminal-refresh? +

Yes. Add a rate_limit block to the terminal-refresh 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 terminal-refresh completely? +

Set action: deny in the PolicyLayer policy for terminal-refresh. 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 terminal-refresh? +

terminal-refresh is provided by the Mcp Terminal MCP server (unfathomable-siren38/mcp-terminal-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.