memory_set · Memory MCP: Risk & Policy

WHAT IT DOES

What memory_set does on Memory

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

WHY IT NEEDS A POLICY

Why memory_set needs a policy

This tool creates or modifies data (memory entries) in a reversible manner. While it permanently records new versions, the write itself is not irreversible—prior versions are preserved and accessible via the sibling memory_rollback and memory_history tools. This falls squarely into Write category.

From the tool's definition Tool description explicitly states 'Create or update a memory entry', which are reversible write operations.

Risk signalsBulk/mass operation — affects multiple targets

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

memory_set Rate-limited

memory_set 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_set": {
      "limits": [
        {
          "counter": "memory_set_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 Memory, so you can run agents against it safely.

FAQ

Questions about memory_set

What does the memory_set tool do? +

Create or update a memory entry. Creates a version snapshot on every write. It is categorised as a Write tool in the 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 memory_set? +

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

What risk level is memory_set? +

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

Can I rate-limit memory_set? +

Yes. Add a rate_limit block to the memory_set 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_set completely? +

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

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