updateMemory · MCP Memory MCP: Risk & Policy

WHAT IT DOES

What updateMemory does on MCP Memory

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

WHY IT NEEDS A POLICY

Why updateMemory needs a policy

The tool creates or modifies data in a reversible manner (classic Write category). While it operates on user preferences and information, the modification is not destructive and could theoretically be reverted by subsequent updates.

From the tool's definition Tool description states it 'updates an existing memory', which modifies data reversibly. The server manages user information and preferences stored in vector search indices. updateMemory allows changes to stored records without permanent deletion.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

updateMemory Rate-limited

updateMemory 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": {
    "updateMemory": {
      "limits": [
        {
          "counter": "updatememory_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, so you can run agents against it safely.

FAQ

Questions about updateMemory

What does the updateMemory tool do? +

This tool updates an existing memory. It is categorised as a Write tool in the MCP Memory MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on updateMemory? +

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

What risk level is updateMemory? +

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

Can I rate-limit updateMemory? +

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

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

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