Delete a file from the CNC controller
AI agents call delete_sd_file to permanently remove resources in Cnc Fluidnc — typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
This tool permanently removes files from the CNC controller's SD card, which cannot be undone. File deletion is irreversible, fitting the Destructive category. Severity is high because accidental deletion of critical G-code programs, macros, or configuration files could halt CNC operations and require manual recovery or re-upload of files.
From the tool's definition Tool name 'delete_sd_file' and description 'Delete a file from the CNC controller' explicitly indicate irreversible deletion of data from the SD card storage.
Attacks that exploit this kind of access
Delete a file from the CNC controller. It is categorised as a Destructive tool in the Cnc Fluidnc MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the Cnc Fluidnc MCP server in PolicyLayer and add a rule for delete_sd_file: 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 Cnc Fluidnc. Nothing to install.
delete_sd_file 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 delete_sd_file 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 delete_sd_file. 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.
delete_sd_file is provided by the Cnc Fluidnc MCP server (whitneydesignlabs/cnc-fluidnc-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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