setup_stack · MCPEmulate MCP: Risk & Policy

WHAT IT DOES

What setup_stack does on MCPEmulate

AI agents use setup_stack 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 setup_stack needs a policy

This tool modifies the emulator's memory layout by mapping a new stack region and updating the stack pointer register. It creates/modifies state within the emulation session, which is reversible (the emulator session can be destroyed or reset). No code is executed, no data is deleted, and no financial transactions occur. It is a Write operation — setting up memory and registers in the emulated environment.

From the tool's definition Map a stack region and set SP to the top

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

setup_stack Rate-limited

setup_stack 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": {
    "setup_stack": {
      "limits": [
        {
          "counter": "setup_stack_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 setup_stack

What does the setup_stack tool do? +

Map a stack region and set SP to the top. 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 setup_stack? +

Register the MCPEmulate MCP server in PolicyLayer and add a rule for setup_stack: 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 setup_stack? +

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

Can I rate-limit setup_stack? +

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

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

setup_stack 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.