expand-code · Macroforge MCP Server MCP: Risk & Policy

WHAT IT DOES

What expand-code does on Macroforge MCP Server

AI agents invoke expand-code to trigger actions in Macroforge MCP Server. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why expand-code needs a policy

This tool executes a code transformation pipeline on user-provided TypeScript code, expanding macros and generating new code. While it returns a result rather than persisting changes, it runs execution logic (macro expansion, code generation) on arbitrary input, placing it in the Execute category.

From the tool's definition 'Expands Macroforge macros in TypeScript code and returns the transformed result' — the tool actively processes and transforms code, running macro expansion logic on arbitrary TypeScript input.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

expand-code Rate-limited

expand-code stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "expand-code": {
      "limits": [
        {
          "counter": "expand-code_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Macroforge MCP Server, so you can run agents against it safely.

FAQ

Questions about expand-code

What does the expand-code tool do? +

Expands Macroforge macros in TypeScript code and returns the transformed result. Shows: - The fully expanded TypeScript code with all generated methods - Any diagnostics (errors, warnings, info) with line/column locations - Help text for fixing issues (when available) Useful for: - Seeing what code the macros generate - Understanding how @derive decorators transform your classes - Debugging macro expansion issues. It is categorised as a Execute tool in the Macroforge MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on expand-code? +

Register the Macroforge MCP Server MCP server in PolicyLayer and add a rule for expand-code: 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 Macroforge MCP Server. Nothing to install.

What risk level is expand-code? +

expand-code is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit expand-code? +

Yes. Add a rate_limit block to the expand-code 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 expand-code completely? +

Set action: deny in the PolicyLayer policy for expand-code. 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 expand-code? +

expand-code is provided by the Macroforge MCP Server MCP server (macroforge-ts/mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.