ssh_shell_start · SSH MCP Server MCP: Risk & Policy

WHAT IT DOES

What ssh_shell_start does on SSH MCP Server

AI agents invoke ssh_shell_start to trigger actions in SSH MCP Server. 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 ssh_shell_start needs a policy

This tool initiates an interactive shell on a remote system, which allows execution of arbitrary commands with effects determined entirely by the AI agent's instructions.

From the tool's definition Tool enables starting an 'interactive shell session' with a returned 'shell ID for sending commands and reading output'.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

ssh_shell_start Rate-limited

ssh_shell_start 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": {
    "ssh_shell_start": {
      "limits": [
        {
          "counter": "ssh_shell_start_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 SSH MCP Server, so you can run agents against it safely.

FAQ

Questions about ssh_shell_start

What does the ssh_shell_start tool do? +

Start an interactive shell session. Returns a shell ID for sending commands and reading output. It is categorised as a Execute tool in the SSH MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on ssh_shell_start? +

Register the SSH MCP Server MCP server in PolicyLayer and add a rule for ssh_shell_start: 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 SSH MCP Server. Nothing to install.

What risk level is ssh_shell_start? +

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

Can I rate-limit ssh_shell_start? +

Yes. Add a rate_limit block to the ssh_shell_start 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_shell_start completely? +

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

ssh_shell_start is provided by the SSH MCP Server MCP server (kpanuragh/ssh-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.