pool_replace_disk
Replace a disk in a pool (destructive — requires confirm)
This record as markdown: /tools/spranab-truenas-mcp/pool-replace-disk.md
What pool_replace_disk does on Truenas
AI agents call pool_replace_disk 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.
Why pool_replace_disk is rated Critical
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)
Attacks that exploit this kind of access
The rule that runs pool_replace_disk 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 pool_replace_disk, this is the rule to start with:
pool_replace_disk is removed from the agent's tool list entirely, so the agent never calls it. The rest of the server keeps working.
The button opens the PolicyLayer dashboard: create your workspace, connect Truenas, apply this rule, and every pool_replace_disk call is checked against it from then on.
Questions about pool_replace_disk
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.
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.
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.
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.
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.
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.
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