AI agents call delete_tool to permanently remove resources in Open WebUI MCP Server — typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
This tool permanently removes a tool from the Open WebUI system. Deletion is irreversible and cannot be undone through normal operations. While the blast radius is somewhat contained to tool configuration rather than user data or financial systems, the irreversibility and administrative nature of the action place it in the Destructive category with high severity.
From the tool's definition Tool name is 'delete_tool' and description states 'Delete a tool.' The verb 'delete' is explicit and indicates irreversible removal of data/resources.
Documented attack patterns abuse exactly the kind of access delete_tool gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Open WebUI MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for delete_tool:
{
"version": "1",
"default": "deny",
"hide": [
"delete_tool"
]
}delete_tool disappears from the agent's tool list entirely, and any attempt to call it is denied. The rest of the server keeps working.
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Delete a tool. It is categorised as a Destructive tool in the Open WebUI MCP Server MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the Open WebUI MCP Server MCP server in PolicyLayer and add a rule for delete_tool: 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 Open WebUI MCP Server. Nothing to install.
delete_tool 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_tool 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_tool. 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_tool is provided by the Open WebUI MCP Server MCP server (troylar/open-webui-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Open WebUI MCP Server, 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.
82 Open WebUI MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.