serial_set_dtr · MCP Remote Access MCP: Risk & Policy

WHAT IT DOES

What serial_set_dtr does on MCP Remote Access

AI agents invoke serial_set_dtr to trigger actions in MCP Remote Access. 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 serial_set_dtr needs a policy

Setting the DTR line triggers an external hardware operation on a remote device, potentially causing a device reset. This is an active control action with real-world hardware effects, making it Execute. While a reset is disruptive, it is generally recoverable (not permanently destructive), but misuse could interrupt running processes or cause data loss on embedded/IoT devices.

From the tool's definition Set DTR (Data Terminal Ready) line state. Used for device reset on many boards.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

serial_set_dtr Rate-limited

serial_set_dtr 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": {
    "serial_set_dtr": {
      "limits": [
        {
          "counter": "serial_set_dtr_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 MCP Remote Access, so you can run agents against it safely.

FAQ

Questions about serial_set_dtr

What does the serial_set_dtr tool do? +

Set DTR (Data Terminal Ready) line state. Used for device reset on many boards. It is categorised as a Execute tool in the MCP Remote Access MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on serial_set_dtr? +

Register the MCP Remote Access MCP server in PolicyLayer and add a rule for serial_set_dtr: 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 MCP Remote Access. Nothing to install.

What risk level is serial_set_dtr? +

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

Can I rate-limit serial_set_dtr? +

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

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

serial_set_dtr is provided by the MCP Remote Access MCP server (rfingadam/mcp-remote-access). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.