cronjob_update

Update an existing cron job

SERVERTruenas SOURCEspranab/truenas-mcp

Medium RISK CLASS

Category Write

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/spranab-truenas-mcp/cronjob-update.md

WHAT IT DOES

What cronjob_update does on Truenas

AI agents use cronjob_update to create or update resources in Truenas, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Truenas environment.

RISK

Why cronjob_update is rated Medium

This tool modifies cron job configurations (a Write action) rather than executing jobs or deleting them. While cron jobs can trigger arbitrary actions when executed, this tool only updates their definition, making changes reversible.

From the tool's definition Tool name 'cronjob_update' and description 'Update an existing cron job' indicate modification of scheduled task configuration. The verb 'update' represents reversible data modification.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs cronjob_update safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Truenas, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For cronjob_update, this is the rule to start with:

cronjob_update Rate-limited

cronjob_update stays usable, but capped: an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "cronjob_update": {
      "limits": [
        {
          "counter": "cronjob_update_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Truenas, apply this rule, and every cronjob_update call is checked against it from then on.

FAQ

Questions about cronjob_update

What does the cronjob_update tool do? +

Update an existing cron job. It is categorised as a Write tool in the Truenas MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on cronjob_update? +

Register the Truenas MCP server in PolicyLayer and add a rule for cronjob_update: 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 cronjob_update? +

cronjob_update is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit cronjob_update? +

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

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

cronjob_update 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.

KEEP EXPLORING

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aroflo_create_or_update_record on AroFlo MCP →team_manager_update_budget on Team Manager MCP → The MCP Attack Database →

Guides

Govern customer-ops agents →Argument validation →Scoped token →