tunable_delete

THE RISK

Critical Risk

Why tunable_delete needs a policy

The tool irreversibly deletes system tunables (kernel/system configuration parameters) from TrueNAS. Tunables are persistent configuration settings; deletion cannot be undone without manual reconfiguration or backups. This is a destructive operation that could impact system stability or behavior if critical tunables are deleted.

From the tool's definition Delete a tunable by its ID — explicit deletion operation on system configuration parameters that cannot be trivially restored without knowing previous values.

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

POLICY

How to control tunable_delete

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

policy.json

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

tunable_delete 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 — 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 tools

Destructive acme_dns_authenticator_delete Delete an ACME DNS authenticator by its ID. Destructive alertservice_delete Delete an alert notification service by its ID. Use alertservice_list to find the ID. Destructive api_key_delete Delete an API key by its numeric ID. Use api_key_list to find the ID. This immediately rev Destructive app_delete Delete/uninstall an app. This is a DESTRUCTIVE operation. The Destructive bootenv_delete Delete a boot environment. This is a DESTRUCTIVE operation — the Destructive certificate_delete Delete a certificate by its ID. This is a DESTRUCTIVE operation — the Destructive cloud_backup_delete Delete a cloud backup task (destructive — requires confirm) Destructive cloudsync_credentials_delete Delete a cloud sync credential

All 279 Truenas 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 → 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 tunable_delete

What does the tunable_delete tool do? +

Delete a tunable by its ID. Use tunable_list to find the ID. It is categorised as a Destructive tool in the Truenas 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 tunable_delete? +

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

What risk level is tunable_delete? +

tunable_delete 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 tunable_delete? +

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

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

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

Enforce policy on every Truenas tool call.

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

CHECK YOUR STACK →