AI agents call memento_recall to retrieve information from Memento Vault without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The tool appears to retrieve or recall stored notes/knowledge from the vault based on its name and the server's stated purpose of 'persistent knowledge capture and retrieval'. This is a read operation with no side effects. Confidence is moderate (0.7) due to missing tool description, but context from siblings and server function strongly suggest retrieval semantics.
From the tool's definition Tool name 'memento_recall' suggests retrieval of stored information. Server description explicitly lists 'reading notes via MCP tools' as a capability. Sibling tools include 'memento_get' and 'memento_search' (both read operations) and 'memento_list'.
Documented attack patterns abuse exactly the kind of access memento_recall gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Memento Vault, and nothing reaches the server without passing your rules. This is the rule we recommend for memento_recall:
{
"version": "1",
"default": "deny",
"tools": {
"memento_recall": {}
}
}memento_recall is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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memento_recall. It is categorised as a Read tool in the Memento Vault MCP Server, which means it retrieves data without modifying state.
Register the Memento Vault MCP server in PolicyLayer and add a rule for memento_recall: 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 Memento Vault. Nothing to install.
memento_recall is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the memento_recall 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 memento_recall. 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.
memento_recall is provided by the Memento Vault MCP server (sandsower/memento-vault). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Memento Vault, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
14 Memento Vault tools catalogued and risk-classified — across an index of 43,000+ MCP servers.