Delete all expired resource locks. Notifies holding agents via conversations DM.
AI agents call clean_expired_locks to permanently remove resources in Mementos — typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
The tool deletes resource locks, which is an irreversible operation that cannot be undone. While the scope is limited to 'expired' locks (making it somewhat constrained), deletion is inherently destructive. The notification of holding agents via DM is a side effect but does not change the destructive nature of the primary action. This is more severe than Write (reversible modification) due to the permanent deletion.
From the tool's definition Tool description explicitly states 'Delete all expired resource locks' - uses the word 'Delete' which indicates irreversible removal of data.
Attacks that exploit this kind of access
Delete all expired resource locks. Notifies holding agents via conversations DM. It is categorised as a Destructive tool in the Mementos MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the Mementos MCP server in PolicyLayer and add a rule for clean_expired_locks: 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 Mementos. Nothing to install.
clean_expired_locks 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 clean_expired_locks 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 clean_expired_locks. 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.
clean_expired_locks is provided by the Mementos MCP server (@hasna/mementos). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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