install_app · Truenas Ws MCP: Risk & Policy

WHAT IT DOES

What install_app does on Truenas Ws

AI agents invoke install_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 install_app needs a policy

Installing an app executes an external operation that modifies system state by deploying software. While not purely destructive (it creates rather than deletes), it goes beyond a simple write — it runs installation processes, potentially pulls images, configures services, and has significant side effects depending on the app being installed.

From the tool's definition 'Install an app from the catalog' — triggers an external installation operation that deploys software onto the system

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

install_app Rate-limited

install_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": {
    "install_app": {
      "limits": [
        {
          "counter": "install_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 install_app

What does the install_app tool do? +

Install an app from the catalog. 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 install_app? +

Register the Truenas Ws MCP server in PolicyLayer and add a rule for install_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 install_app? +

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

Can I rate-limit install_app? +

Yes. Add a rate_limit block to the install_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 install_app completely? +

Set action: deny in the PolicyLayer policy for install_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 install_app? +

install_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.