terminal-resize · Mcp Terminal MCP: Risk & Policy

WHAT IT DOES

What terminal-resize does on Mcp Terminal

AI agents invoke terminal-resize 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-resize needs a policy

Resizing a PTY (pseudo-terminal) is an operational action that modifies the terminal session's state. While it doesn't run code or delete data, it does trigger an external operation affecting a live terminal session. The blast radius is low since resizing a terminal is reversible and has minimal side effects, but it does interact with an active process/session beyond simple data retrieval or storage.

From the tool's definition Resizes the PTY to match the UI terminal dimensions

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

terminal-resize Rate-limited

terminal-resize 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-resize": {
      "limits": [
        {
          "counter": "terminal-resize_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-resize

What does the terminal-resize tool do? +

Resizes the PTY to match the UI terminal dimensions. 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-resize? +

Register the Mcp Terminal MCP server in PolicyLayer and add a rule for terminal-resize: 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-resize? +

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

Can I rate-limit terminal-resize? +

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

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

terminal-resize 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.