add_symbol · MCPEmulate MCP: Risk & Policy

WHAT IT DOES

What add_symbol does on MCPEmulate

AI agents use add_symbol 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 add_symbol needs a policy

This tool creates or modifies metadata (symbol-to-address mappings) within an isolated emulation session. It does not execute code, delete data irreversibly, or affect external systems, but it does change the internal state of the emulator.

From the tool's definition Tool modifies emulator state by 'Associate[ing] a symbolic name with a memory address' — creating or updating symbol table entries. This is a write operation that changes the debugging/analysis context of an emulation session.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_symbol Rate-limited

add_symbol 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": {
    "add_symbol": {
      "limits": [
        {
          "counter": "add_symbol_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 add_symbol

What does the add_symbol tool do? +

Associate a symbolic name with a memory address. 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 add_symbol? +

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

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

Can I rate-limit add_symbol? +

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

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

add_symbol 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.