AI agents call callback_clear to permanently remove resources in Zebbern Kali MCP — typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
The description is empty, which lowers confidence. However, the name 'callback_clear' on a penetration testing platform suggests clearing callback/listener configurations, reverse shell listeners, or C2 callback records — an action that would be irreversible and destructive in nature.
From the tool's definition Tool name 'callback_clear' on a Kali Linux penetration testing MCP server with sibling tools including secretsdump, psexec, wmiexec, and various AD attack tools.
Documented attack patterns abuse exactly the kind of access callback_clear gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Zebbern Kali MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for callback_clear:
{
"version": "1",
"default": "deny",
"hide": [
"callback_clear"
]
}callback_clear 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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callback_clear. It is categorised as a Destructive tool in the Zebbern Kali MCP MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the Zebbern Kali MCP server in PolicyLayer and add a rule for callback_clear: 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 Zebbern Kali MCP. Nothing to install.
callback_clear 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 callback_clear 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 callback_clear. 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.
callback_clear is provided by the Zebbern Kali MCP server (zebbern/zebbern-kali-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 128 Zebbern Kali MCP tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
128 Zebbern Kali MCP tools catalogued and risk-classified — across an index of 42,500+ MCP servers.