Can the AI change device settings?

The two write tools only work when the target is 127.0.0.1 or localhost (this PC); any other address is refused before connecting. The check is by address only, so if a program on this PC forwards to another device (a TCP relay, gateway, SSH tunnel …), a write can reach a real device — do not use the write tools while such a program is running.

What does it send out?

PortDock MCP itself only talks to the device addresses and ports you give, and the session log stays on this PC. Tool results go to the AI client you use, so from there that client's policy applies.

PortDock MCP

A windowless MCP server started by AI clients (Claude Desktop, VS Code, Cursor …). The AI reads this PC's COM ports and network adapters and reads Modbus, MC protocol and SCPI values from devices you name. The write tools accept only this PC's address (127.0.0.1) and are meant for simulators. Note that if a program on this PC forwards to another device (a TCP relay, gateway or tunnel), a write can reach a real device.

Free · Windows 10 and 11 · no ads in the program · open source (GPL-3.0)

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Made for

Anyone who wants an AI assistant to look at COM port and USB adapter problems with them
Developers who want to read Modbus, MC or SCPI values inside an AI conversation
People practising AI tool use against simulators instead of real devices

Features

Nine read tools

COM port list, Port Inspector report, serial listening (sends nothing), Modbus reads (FC 01–04), MC 3E batch read, SCPI queries, ping, network adapters and device register maps.

Writes only to 127.0.0.1 simulators

Practise «write, then read back» with Modbus Slave or PLC Simulator on this PC. Any other address is refused before connecting (the check is by address only — do not use it with a relay program running).

SCPI queries only

Sends one query ending with «?»; ones that can change state, such as *TST?, *CAL? and *RST, are refused. READ? and MEAS…?, which start a new measurement, are refused by default and sent only when you allow it with allow_measure (since 0.8.0). Use FETC? to read just the last value.

Session log and rate limits

Every call is kept on this PC as JSON lines and never sent out. The same target at most once per 100 ms, 120 calls a minute.

Personal data masked

User folder paths in results become «~», MAC addresses «xx-…» and network names «(hidden)».

One file to install

No Python, Node or Docker: a .mcpb (open in Claude Desktop) or a single exe in a zip.

Quick start

Open PortDock-MCP.mcpb in Claude Desktop (other clients: put the exe path from the zip in their settings)
Ask the AI something like «list my COM ports» — the client asks you before each tool call
Give the address, port and unit to read a device. Practise with Modbus Slave or PLC Simulator on 127.0.0.1

Read the full guide →