write_memory · MCPEmulate MCP: Risk & Policy

WHAT IT DOES

What write_memory does on MCPEmulate

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

WHY IT NEEDS A POLICY

Why write_memory needs a policy

This tool modifies memory within an isolated CPU emulator session, which is a reversible write operation. It does not delete data (Destructive), execute arbitrary code outside the emulator (Execute), involve financial transactions (Financial), or require special Read classification.

From the tool's definition Tool name 'write_memory' and description 'Write data to emulator memory' directly indicate data modification within an isolated emulation context.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

write_memory Rate-limited

write_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": {
    "write_memory": {
      "limits": [
        {
          "counter": "write_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 MCPEmulate, so you can run agents against it safely.

FAQ

Questions about write_memory

What does the write_memory tool do? +

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

How do I enforce a policy on write_memory? +

Register the MCPEmulate MCP server in PolicyLayer and add a rule for write_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 MCPEmulate. Nothing to install.

What risk level is write_memory? +

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

Can I rate-limit write_memory? +

Yes. Add a rate_limit block to the write_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 write_memory completely? +

Set action: deny in the PolicyLayer policy for write_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 write_memory? +

write_memory is provided by the MCPEmulate MCP server (labguy94/mcpemulate). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.