AI agents call cronjob_delete to permanently remove resources in Truenas — typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
Deleting a cron job permanently removes scheduled automation tasks. This is irreversible—once deleted, the job must be manually recreated. The impact depends on what the cron job does (could affect backups, maintenance tasks, security monitoring, etc.), justifying 'high' severity. Confidence is high due to explicit 'delete' action and destructive nature.
From the tool's definition Tool name: 'cronjob_delete' with description 'Delete a cron job'. The verb 'delete' combined with the destructive action of removing a scheduled cron job indicates an irreversible operation that cannot be undone.
Documented attack patterns abuse exactly the kind of access cronjob_delete gives an agent:
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 cronjob_delete:
{
"version": "1",
"default": "deny",
"hide": [
"cronjob_delete"
]
}cronjob_delete disappears from the agent's tool list entirely, and any attempt to call it is denied. The rest of the server keeps working.
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Delete a cron job. 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.
Register the Truenas MCP server in PolicyLayer and add a rule for cronjob_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.
cronjob_delete is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.
Yes. Add a rate_limit block to the cronjob_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.
Set action: deny in the PolicyLayer policy for cronjob_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.
cronjob_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.
Start from Truenas, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
279 Truenas tools catalogued and risk-classified — across an index of 43,000+ MCP servers.