hippo_fact_forget_with_undo
Cycle 2026-05-27 round 13 P0c. Delete one fact AND emit
This record as markdown: /tools/verimem/hippo-fact-forget-with-undo.md
What hippo_fact_forget_with_undo does on Verimem
AI agents call hippo_fact_forget_with_undo to permanently remove resources in Verimem, typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
Why hippo_fact_forget_with_undo is rated Critical
This tool permanently removes facts from the memory system. Even though an undo mechanism may be available (lowering severity from critical), the core action is irreversible data deletion without user confirmation in the description, making it Destructive category. In a memory management context for AI agents, deleting facts could corrupt historical records or cause loss of critical context.
From the tool's definition Tool name explicitly contains 'forget' and description states 'Delete one fact' — irreversible deletion of stored data. The mention of 'undo' suggests rollback capability exists, but the primary action is destructive deletion.
Attacks that exploit this kind of access
The rule that runs hippo_fact_forget_with_undo safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Verimem, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For hippo_fact_forget_with_undo, this is the rule to start with:
hippo_fact_forget_with_undo 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 Verimem, apply this rule, and every hippo_fact_forget_with_undo call is checked against it from then on.
Questions about hippo_fact_forget_with_undo
Cycle 2026-05-27 round 13 P0c. Delete one fact AND emit. It is categorised as a Destructive tool in the Verimem MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the Verimem MCP server in PolicyLayer and add a rule for hippo_fact_forget_with_undo: 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 Verimem. Nothing to install.
hippo_fact_forget_with_undo 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 hippo_fact_forget_with_undo 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 hippo_fact_forget_with_undo. 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.
hippo_fact_forget_with_undo is provided by the Verimem MCP server (aureliocpr-ctrl/verimem). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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