pty_kill · Pty MCP: Risk & Policy

WHAT IT DOES

What pty_kill does on Pty

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

WHY IT NEEDS A POLICY

Why pty_kill needs a policy

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

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

pty_kill Rate-limited

pty_kill 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": {
    "pty_kill": {
      "limits": [
        {
          "counter": "pty_kill_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 Pty, so you can run agents against it safely.

FAQ

Questions about pty_kill

What does the pty_kill tool do? +

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

How do I enforce a policy on pty_kill? +

Register the Pty MCP server in PolicyLayer and add a rule for pty_kill: 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 Pty. Nothing to install.

What risk level is pty_kill? +

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

Can I rate-limit pty_kill? +

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

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

pty_kill is provided by the Pty MCP server (reedm121/pty-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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