ssh_forward_close · Mcpx MCP: Risk & Policy

WHAT IT DOES

What ssh_forward_close does on Mcpx

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

WHY IT NEEDS A POLICY

Why ssh_forward_close needs a policy

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

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

ssh_forward_close Rate-limited

ssh_forward_close 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": {
    "ssh_forward_close": {
      "limits": [
        {
          "counter": "ssh_forward_close_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 Mcpx, so you can run agents against it safely.

FAQ

Questions about ssh_forward_close

What does the ssh_forward_close tool do? +

Close an SSH port forward by id. It is categorised as a Write tool in the Mcpx MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on ssh_forward_close? +

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

What risk level is ssh_forward_close? +

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

Can I rate-limit ssh_forward_close? +

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

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

ssh_forward_close is provided by the Mcpx MCP server (rmednitzer/relay-shell). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.