AI agents call clearHistory to permanently remove resources in Mup — typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
Clearing chat history is a destructive operation that removes data irreversibly. Even if an archive is created, the original chat state is wiped and cannot be recovered through normal tool operations. This poses a high blast radius if an agent accidentally clears important conversation history, context, or records.
From the tool's definition Tool description states 'clear the chat', which irreversibly removes message history. While 'archive' suggests a backup, the primary action is clearing/deleting data that cannot be undone by the tool itself.
Documented attack patterns abuse exactly the kind of access clearHistory gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Mup, and nothing reaches the server without passing your rules. This is the rule we recommend for clearHistory:
{
"version": "1",
"default": "deny",
"hide": [
"clearHistory"
]
}clearHistory 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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Archive current messages and clear the chat. It is categorised as a Destructive tool in the Mup MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the Mup MCP server in PolicyLayer and add a rule for clearHistory: 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 Mup. Nothing to install.
clearHistory 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 clearHistory 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 clearHistory. 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.
clearHistory is provided by the Mup MCP server (mup-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Mup, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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6 Mup tools catalogued and risk-classified — across an index of 43,000+ MCP servers.