forget

THE RISK

Critical Risk

Why forget needs a policy

The forget tool performs permanent deletion of stored memories and entities without possibility of recovery, fitting the Destructive category. While the absolute blast radius is bounded by the scope of stored memories (not system-wide or financial data), the severity is high because an AI agent misusing this could permanently erase user knowledge, context, or critical information the user intended to retain, with no…

From the tool's definition Tool description states 'Delete a specific memory or an entire entity and all its associated data' and explicitly warns 'this is permanent.' The forget tool irreversibly removes data from the memory graph.

Documented attack patterns abuse exactly the kind of access forget gives an agent:

POLICY

How to control forget

PolicyLayer is an MCP gateway — it sits between your AI agents and Hippocampus, and nothing reaches the server without passing your rules. This is the rule we recommend for forget:

policy.json

{
  "version": "1",
  "default": "deny",
  "hide": [
    "forget"
  ]
}

forget disappears from the agent's tool list entirely, and any attempt to call it is denied. The rest of the server keeps working.

Create a free account and register Hippocampus — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

RESTRICT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Hippocampus tools

Destructive merge_entities Merge multiple entities into one. Moves all observations, embeddings, and relationships fr Write merge Merge multiple observations into one. Atomic operation: provide merged text + list of obse Write onboard Bootstrap memory from the current AI session. Returns extraction instructions — follow the Write remember Store a memory or piece of information. Use this to save facts, preferences, decisions, re Write update Replace an existing observation with new content. Finds the old observation by exact conte Read check_version Check if cached entity content is still current. Pass a previously received version_hash t Read context Get full context about a topic: the entity, its observations, relationships, and related e Read recall Search memories by semantic similarity and keyword match. Returns relevant stored informat

All 11 Hippocampus tools →

Destructive tools on other servers

Android Forensics ADB MCP Server create_full_backup 0xarchive web3_revoke_key Frida Game Hacking MCP clear_scan cPanel MCP Server clear_spam_box

Go deeper

Critical-risk tools in Hippocampus → Every critical-risk tool this server exposes, in one view.
All critical-risk MCP tools → Every critical-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Blast radius → How much damage one compromised or confused agent can do — and how to bound it.
Tool call approval → Approval gates on individual tool calls: auto-allow, prompt, or deny.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about forget

What does the forget tool do? +

Delete a specific memory or an entire entity and all its associated data. Use with care — this is permanent. It is categorised as a Destructive tool in the Hippocampus MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.

How do I enforce a policy on forget? +

Register the Hippocampus MCP server in PolicyLayer and add a rule for forget: 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 Hippocampus. Nothing to install.

What risk level is forget? +

forget is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.

Can I rate-limit forget? +

Yes. Add a rate_limit block to the forget 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.

How do I block forget completely? +

Set action: deny in the PolicyLayer policy for forget. 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.

What MCP server provides forget? +

forget is provided by the Hippocampus MCP server (karrolcia/hippocampus). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Hippocampus tool call.

Start from Hippocampus, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →