AI agents use bootenv_keep 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.
Based on the name, this tool likely sets or clears a 'keep' flag on TrueNAS boot environments, which is a reversible write operation that marks a boot environment to prevent deletion. The description is truncated so confidence is reduced. This is a Write operation as it modifies metadata/flags rather than deleting or executing code.
From the tool's definition Tool name 'bootenv_keep' suggests setting or clearing a keep flag on boot environments; description is truncated and uninformative: 'Set or clear the'
Documented attack patterns abuse exactly the kind of access bootenv_keep 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 bootenv_keep:
{
"version": "1",
"default": "deny",
"tools": {
"bootenv_keep": {
"limits": [
{
"counter": "bootenv_keep_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}bootenv_keep 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 or clear the. 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 bootenv_keep: 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.
bootenv_keep 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 bootenv_keep 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 bootenv_keep. 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.
bootenv_keep 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.
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279 Truenas tools catalogued and risk-classified — across an index of 43,000+ MCP servers.