stop_app · Truenas Ws MCP: Risk & Policy

WHAT IT DOES

What stop_app does on Truenas Ws

AI agents invoke stop_app to trigger actions in Truenas Ws. 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 stop_app needs a policy

Stopping an app is an Execute action rather than Write because it triggers a discrete external operation (service termination) rather than data modification. It is less severe than Destructive (data loss) or Financial but more severe than Read. Medium severity reflects that stopping apps can disrupt services and availability, but effects are typically reversible (apps can be restarted).

From the tool's definition Tool name 'stop_app' and description 'Stop a running app' indicate the tool triggers an external operation (halting a service/container) whose effects depend on which app is targeted. This is a state-changing action that executes against infrastructure.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

stop_app Rate-limited

stop_app 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": {
    "stop_app": {
      "limits": [
        {
          "counter": "stop_app_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 Truenas Ws, so you can run agents against it safely.

FAQ

Questions about stop_app

What does the stop_app tool do? +

Stop a running app. It is categorised as a Execute tool in the Truenas Ws MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on stop_app? +

Register the Truenas Ws MCP server in PolicyLayer and add a rule for stop_app: 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 Truenas Ws. Nothing to install.

What risk level is stop_app? +

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

Can I rate-limit stop_app? +

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

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

stop_app is provided by the Truenas Ws MCP server (thoriphes/truenas-ws-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.