writeMemory · VICE C64 Emulator MCP Server MCP

WHAT IT DOES

What writeMemory does on VICE C64 Emulator MCP Server

AI agents use writeMemory to create or update resources in VICE C64 Emulator MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your VICE C64 Emulator MCP Server environment.

WHY IT NEEDS A POLICY

Why writeMemory needs a policy

This tool writes arbitrary bytes to memory locations in the C64 emulator. While the emulator context limits real-world impact, misuse could corrupt program state, overwrite critical memory regions (e.g., zero page, stack, I/O registers), or destabilize the debugging session.

From the tool's definition 'Write bytes to the C64' — directly modifies memory in the emulated C64 system

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

writeMemory Rate-limited

writeMemory 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": {
    "writeMemory": {
      "limits": [
        {
          "counter": "writememory_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 VICE C64 Emulator MCP Server, so you can run agents against it safely.

FAQ

Questions about writeMemory

What does the writeMemory tool do? +

Write bytes to the C64. It is categorised as a Write tool in the VICE C64 Emulator MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on writeMemory? +

Register the VICE C64 Emulator MCP Server MCP server in PolicyLayer and add a rule for writeMemory: 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 VICE C64 Emulator MCP Server. Nothing to install.

What risk level is writeMemory? +

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

Can I rate-limit writeMemory? +

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

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

writeMemory is provided by the VICE C64 Emulator MCP Server MCP server (simen/vice-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.