mem_save · Crossmem MCP: Risk & Policy

WHAT IT DOES

What mem_save does on Crossmem

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

WHY IT NEEDS A POLICY

Why mem_save needs a policy

The tool appears to save or store data based on its name and the server's stated purpose of enabling knowledge persistence. This is a reversible write operation (data can be modified or deleted later via mem_forget). It is not Destructive because saving is reversible, not Execute because it doesn't run external code, and not Financial.

From the tool's definition Tool name is 'mem_save' and the server description indicates it enables AI assistants to 'save cross-project knowledge'. The name and context strongly suggest this tool creates or modifies data in a memory/knowledge system.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

mem_save Rate-limited

mem_save 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": {
    "mem_save": {
      "limits": [
        {
          "counter": "mem_save_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 Crossmem, so you can run agents against it safely.

FAQ

Questions about mem_save

What does the mem_save tool do? +

mem_save. It is categorised as a Write tool in the Crossmem MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on mem_save? +

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

What risk level is mem_save? +

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

Can I rate-limit mem_save? +

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

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

mem_save is provided by the Crossmem MCP server (jamiemoles/crossmem). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.