pool_replace_disk

THE RISK

Critical Risk

Why pool_replace_disk needs a policy

Disk replacement in a storage pool is explicitly labeled as destructive. It irreversibly overwrites the target disk and modifies pool configuration. Misuse could cause data loss or pool degradation across potentially large storage arrays.

From the tool's definition Replace a disk in a pool (destructive — requires confirm)

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

POLICY

How to control pool_replace_disk

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 pool_replace_disk:

policy.json

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

pool_replace_disk 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

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All 279 Truenas tools →

Destructive tools on other servers

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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 pool_replace_disk

What does the pool_replace_disk tool do? +

Replace a disk in a pool (destructive — requires confirm). 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 pool_replace_disk? +

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

pool_replace_disk 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 pool_replace_disk? +

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

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

pool_replace_disk 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 →