memory · Reviewer MCP: Risk & Policy

WHAT IT DOES

What memory does on Reviewer MCP

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

WHY IT NEEDS A POLICY

Why memory needs a policy

The tool both writes (stores) and reads (retrieves) temporary key-value pairs. Since Write is more severe than Read, and the tool explicitly supports storing data, it is classified as Write. The impact is low because data is only held in volatile memory and is lost on server restart, limiting blast radius significantly.

From the tool's definition Store and retrieve temporary key-value pairs in memory (data is lost on MCP server restart)

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

memory Rate-limited

memory 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": {
      "limits": [
        {
          "counter": "memory_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 Reviewer MCP, so you can run agents against it safely.

FAQ

Questions about memory

What does the memory tool do? +

Store and retrieve temporary key-value pairs in memory (data is lost on MCP server restart). It is categorised as a Write tool in the Reviewer MCP 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? +

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

What risk level is memory? +

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

Can I rate-limit memory? +

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

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

memory is provided by the Reviewer MCP server (jaggederest/mcp_reviewer). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.