Set the update configuration. Currently supports changing the update train.
AI agents use update_config_set 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.
The tool modifies system settings (update train configuration) rather than just reading data (Read), but does not delete data (Destructive) or execute arbitrary code (Execute). Update train configuration is a Write operation as it creates or modifies configuration state. Severity is medium because misconfiguring updates could impact system stability and security patch deployment, but the operation is reversible.
From the tool's definition Tool allows modifying TrueNAS SCALE system configuration through 'Set the update configuration' operation. The description explicitly states it changes 'the update train', which configures how system updates are applied.
Documented attack patterns abuse exactly the kind of access update_config_set 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 update_config_set:
{
"version": "1",
"default": "deny",
"tools": {
"update_config_set": {
"limits": [
{
"counter": "update_config_set_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}update_config_set 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.
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Set the update configuration. Currently supports changing the update train. 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.
Register the Truenas MCP server in PolicyLayer and add a rule for update_config_set: 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.
update_config_set is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the update_config_set 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 update_config_set. 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.
update_config_set 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.