Generic SCPI Instrument

Generic SCPI Instrument — MCP Server

Let an AI agent talk to any IEEE 488.2 / SCPI instrument: multimeters, oscilloscopes, source-measure units, power supplies, electronic loads, function generators, spectrum analyzers and counters. It works over GPIB, USBTMC, LAN (VXI-11, HiSLIP, raw socket) and RS-232. Because the agent writes raw SCPI, the server puts the safety in the plumbing. The read path accepts only single queries. Anything that changes the instrument goes through tools the MCP client asks you to confirm. You can give the server command allow and deny lists and a safe-state command of your own.

Keysight or Rohde & Schwarz instrument? Use the vendor's official MCP server instead: Keysight MCP Server for Instrument Control or the MCP server that ships with RsInstrument (python -m RsInstrument.mcp). labmcp-scpi covers everything else: Tektronix/Keithley, Rigol, Siglent, SRS, Aim-TTi, B&K Precision, GW Instek, older HP/Agilent GPIB gear, and more.

Try it without hardware

uvx labmcp-scpi --simulate --check

The simulator is a small, generic bench instrument (*IDN? → LabMCP,SIM-DMM-PSU,SIM000001,1.0.0). It is a 0–30 V / 3 A supply driving a 100 Ω load, with a built-in DMM across the load. It supports MEASure:VOLTage:DC?, CONFigure + READ?/FETCh?, [SOURce:]VOLTage/CURRent, OUTPut[:STATe], TRIGger:COUNt, FORMat[:DATA] REAL,32|64 binary blocks, FORMat:BORDer, *ESR?/*STB?, and a 10-entry SYSTem:ERRor? queue (overflow gives -350). In --simulate mode, the safe state is OUTP OFF.

Connect your instrument

1. Instrument setup: enable the remote interface you want to use.

• LAN: set a fixed IP address. Enable VXI-11/HiSLIP (for VISA) or the SCPI raw-socket server. Many instruments use port 5025 for the socket; check the LAN settings page or the manual.
• USB: select USBTMC / "USB device (TMC)", not "USB mass storage" or a virtual COM port.
• GPIB: note the instrument's GPIB address.
• RS-232: set the baud rate, parity and handshake, and select SCPI as the language if the instrument asks.

1. Find it: uvx labmcp ports, or ask the agent to run list_visa_resources. That tool works without --address and lists VISA resources through pyvisa-py; pass backend=@ivi to use NI-VISA or another vendor VISA library.
2. Test the connection:

   uvx labmcp-scpi --address visa://TCPIP0::192.168.1.50::inst0::INSTR --check      # LAN, VXI-11

uvx labmcp-scpi --address visa://TCPIP0::192.168.1.50::hislip0::INSTR --check # LAN, HiSLIP uvx labmcp-scpi --address tcp://192.168.1.50:5025 --check # raw socket uvx labmcp-scpi --address "visa://USB0::0x1AB1::0x0588::DS1ZA000000::INSTR" --check uvx labmcp-scpi --address "visa://GPIB0::22::INSTR?backend=@ivi" --check # NI-VISA uvx labmcp-scpi --address "serial:///dev/ttyUSB0?baudrate=9600&read_termination=CRLF" --check

   `--check` prints the parsed `*IDN?` reply. If it times out, check the terminator: SCPI uses LF by default, and some serial instruments need `read_termination=CRLF`. Also check the baud rate, and that the instrument is set to SCPI rather than an emulation language.

Add to your MCP client

Claude Code

claude mcp add scope -- uvx labmcp-scpi --address visa://TCPIP0::192.168.1.50::inst0::INSTR

Claude Desktop / Cursor / Windsurf (claude_desktop_config.json, .cursor/mcp.json, …)

{

"mcpServers": { "psu": { "command": "uvx", "args": [ "labmcp-scpi", "--address", "tcp://192.168.1.50:5025", "--option", "safe_state=OUTP OFF", "--option", "write_denylist=^OUTP\\d*(:STAT)? (?!OFF\\b)" ] } } }

Add --read-only to allow only queries. In read-only mode scpi_write, scpi_batch and reset_instrument disappear. device_clear and apply_safe_state stay available. Run one server per instrument, each with its own key (scope, psu, dmm, …).

Tools

get_connection_info, get_command_log and reconnect are built into every LabMCP server. apply_safe_state is listed only when a safe state is configured.

Command policy

A generic server cannot know which SCPI commands are dangerous on *your* instrument. It enforces what it can and lets you add the rest:

Matching rules:

• Patterns are Python regular expressions, matched case-insensitively.
• Each ;-separated message unit is checked in two forms. The first is the unit as sent, upper-cased, with collapsed whitespace and no leading colon. The second reduces every mnemonic to its SCPI short form (SCPI-99 Vol. 1 §6.2.1): :OUTPut1:STATe ON becomes OUTP1:STAT ON. So ^OUTP\d*(:STAT)? (?!OFF\b) catches OUTP ON, outp:stat 1, VOLT 5;:OUTPut:STATe ON and OUTPut2 ON.
• SCPI booleans accept any number (it is rounded, and anything non-zero means ON), so OUTP 2, OUTP 1.0 and OUTP #H1 also switch an output on. Deny "everything except OFF", as above, rather than listing (ON|1).
• The denylist uses re.search. It also resolves relative headers (OUTP:POL NORM;STAT ON is checked as OUTP:STAT ON) and splits at every ;, even inside quotes. The allowlist must match a whole unit.
• Every step of scpi_batch is checked before the first step is sent.

Examples:

# Power supply: the agent may set levels and switch the output OFF, but only a human switches it on

--option 'write_denylist=^OUTP\d*(:STAT)? (?!OFF\b)' --option 'safe_state=OUTP OFF'

DMM: allow measurement configuration only

--option 'write_allowlist=(CONF|SENS|TRIG|INIT|FORM|ABOR)(:\S+)*( .*)?'

SMU: measuring can switch the output on, so require confirmation for it

--option 'query_denylist=^(MEAS|READ)' --option 'safe_state=OUTP OFF'

The environment variable LABMCP_OPTIONS splits on commas. For regular expressions that contain commas, pass t