delete_custom_app

THE RISK

Critical Risk

Why delete_custom_app needs a policy

This tool is destructive because it removes custom apps and their data volumes, which is an irreversible operation that cannot be undone. The optional deletion of data volumes elevates this to Destructive rather than Execute. While the blast radius is significant (app removal, potential data loss), it is limited to the scope of a single TrueNAS instance's custom apps, hence 'high' rather than 'critical' severity.

From the tool's definition 'Delete a Custom App and optionally its data volumes' — the tool permanently removes applications and can irreversibly delete associated data volumes.

Documented attack patterns abuse exactly the kind of access delete_custom_app gives an agent:

POLICY

How to control delete_custom_app

PolicyLayer is an MCP gateway — it sits between your AI agents and TrueNAS Scale MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for delete_custom_app:

policy.json

{
  "version": "1",
  "default": "deny",
  "hide": [
    "delete_custom_app"
  ]
}

delete_custom_app disappears from the agent's tool list entirely, and any attempt to call it is denied. The rest of the server keeps working.

Create a free account and register TrueNAS Scale MCP Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

RESTRICT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More TrueNAS Scale MCP Server tools

Destructive cleanup_stale_containers Clean up stale containers and fix conflicts Execute bulk_app_operation Start/stop multiple apps at once Execute deploy_custom_app Deploy a new Custom App from Docker Compose configuration Execute start_custom_app Start a stopped Custom App Execute stop_custom_app Stop a running Custom App Write update_custom_app Update an existing Custom App with new Docker Compose configuration Read diagnose_docker_issues Diagnose Docker engine issues and network conflicts Read get_app_logs Retrieve logs from a Custom App

All 13 TrueNAS Scale MCP Server tools →

Destructive tools on other servers

Android Forensics ADB MCP Server create_full_backup 0xarchive web3_revoke_key Frida Game Hacking MCP clear_scan cPanel MCP Server clear_spam_box

Go deeper

Critical-risk tools in TrueNAS Scale MCP Server → Every critical-risk tool this server exposes, in one view.
All critical-risk MCP tools → Every critical-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Blast radius → How much damage one compromised or confused agent can do — and how to bound it.
Tool call approval → Approval gates on individual tool calls: auto-allow, prompt, or deny.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about delete_custom_app

What does the delete_custom_app tool do? +

Delete a Custom App and optionally its data volumes. It is categorised as a Destructive tool in the TrueNAS Scale MCP Server MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.

How do I enforce a policy on delete_custom_app? +

Register the TrueNAS Scale MCP Server MCP server in PolicyLayer and add a rule for delete_custom_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 Scale MCP Server. Nothing to install.

What risk level is delete_custom_app? +

delete_custom_app is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.

Can I rate-limit delete_custom_app? +

Yes. Add a rate_limit block to the delete_custom_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 delete_custom_app completely? +

Set action: deny in the PolicyLayer policy for delete_custom_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 delete_custom_app? +

delete_custom_app is provided by the TrueNAS Scale MCP Server MCP server (svnstfns/truenas-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every TrueNAS Scale MCP Server tool call.

Start from TrueNAS Scale MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →