set_fp_registers · MCPEmulate MCP: Risk & Policy

WHAT IT DOES

What set_fp_registers does on MCPEmulate

AI agents use set_fp_registers 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 set_fp_registers needs a policy

This tool modifies floating-point and SIMD register state in an emulated CPU environment. It is Write rather than Execute because it directly updates register values without triggering arbitrary code execution (execution is controlled separately via other tools like assemble_and_load).

From the tool's definition Tool description states 'Write FP/SIMD registers' — the verb 'Write' explicitly indicates modification of emulator state. The tool modifies CPU register values within an isolated emulation session.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

set_fp_registers Rate-limited

set_fp_registers 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": {
    "set_fp_registers": {
      "limits": [
        {
          "counter": "set_fp_registers_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 set_fp_registers

What does the set_fp_registers tool do? +

Write FP/SIMD registers. 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 set_fp_registers? +

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

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

Can I rate-limit set_fp_registers? +

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

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

set_fp_registers 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.