memory_store · MCP Memory Server MCP: Risk & Policy

WHAT IT DOES

What memory_store does on MCP Memory Server

AI agents use memory_store to create or update resources in MCP Memory Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your MCP Memory Server environment.

WHY IT NEEDS A POLICY

Why memory_store needs a policy

This tool writes data to persistent storage (conversational memory) and triggers automatic entity extraction. It creates new records or updates existing memory state across sessions. It is reversible in principle (memories could be deleted), so it falls under Write rather than Destructive.

From the tool's definition 'Store information in conversational memory with automatic entity extraction' — creates/modifies persistent memory records

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

memory_store Rate-limited

memory_store stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "memory_store": {
      "limits": [
        {
          "counter": "memory_store_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches MCP Memory Server, so you can run agents against it safely.

FAQ

Questions about memory_store

What does the memory_store tool do? +

Store information in conversational memory with automatic entity extraction. It is categorised as a Write tool in the MCP Memory Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on memory_store? +

Register the MCP Memory Server MCP server in PolicyLayer and add a rule for memory_store: 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 MCP Memory Server. Nothing to install.

What risk level is memory_store? +

memory_store is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit memory_store? +

Yes. Add a rate_limit block to the memory_store 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 memory_store completely? +

Set action: deny in the PolicyLayer policy for memory_store. 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 memory_store? +

memory_store is provided by the MCP Memory Server MCP server (plumycat/mcp-memory-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.