serial-console-mcp

Let Claude drive your serial console.

 MIT licensed  ·  Python 3.10+  ·  status: experimental (0.3.0)

This adds a few tools to Claude Desktop so you can talk to anything on a serial port — a network device's console/craft port (Juniper, Cisco, etc.), a radio, rotator, amplifier, antenna switch, or a microcontroller — just by asking Claude.

You do not need to know any programming. After it's installed you talk to Claude normally:

You: What serial ports do you see? Claude: I found two. One looks like a Silicon Labs CP210x on COM4 — that's probably your device.

You: Connect to COM4 at 9600 baud. Claude: Connected.

You: Log in and show me the version.

How it works (the important part)

A serial console isn't a simple question-and-answer channel. It echoes what you type, prints unsolicited messages on its own (logs, interface flaps), and can dump pages of output. So the moment a port is open, a background reader keeps draining it into a buffer. That means Claude can:

• send a command (writes only — doesn't guess when the reply is done), then
• read until a prompt appears (# , > , login: …) to capture the whole reply — even a long one — without cutting it off, or
• read whatever's waiting for streaming/unsolicited output.

This is the same model minicom and expect use, which is why it handles interactive CLIs properly.

The tools

Tool	What it does
list_serial_ports	Enumerate ports with description and USB hardware id; marks ones open here
list_presets	Usual settings per device family: Cisco/Juniper/Linux consoles, Kenwood/Elecraft/Yaesu CAT, Icom CI-V, rotators, Arduino, NMEA GPS
connect / reconnect_last / disconnect	Open a port by name. Defaults 9600 8N1, no flow control; baud, data bits, parity, stop bits, RTS/CTS, XON/XOFF, line ending and prompt are all settable, or loaded from a preset. Several ports at once
send_keys / screen	Press Ctrl-C, Esc, Tab, arrows, F-keys by name; view the VT100/xterm screen of a full-screen console (BIOS, BMC, menu switches, vi)
send_text / send_hex	Write an ASCII line (CR / LF / CRLF / none) or raw hex bytes. Write-only
read_until_prompt	Return buffered output up to a literal or regex prompt, leaving the rest; auto_reply pages through --More--
read_available	Return whatever has arrived, as text and hex
query_text	Clear, send, then read until the prompt or until the line goes idle
expect	A scripted list of send-and-wait steps in one call: logins, command sequences
set_lines / pulse_line / send_break	Drive DTR and RTS (PTT, Arduino reset), send BREAK
capture_start / capture_stop / get_transcript	Log a session to a file (raw or timestamped TX/RX); re-read the rolling transcript
port_in_use_by / detect_baud	Which program holds a port; which baud rate produces readable text
cat_build / cat_parse	Kenwood, Elecraft and Yaesu ; commands: build a frequency set, decode ID, FA, MD, IF and error replies
civ_build / civ_parse / civ_freq	Icom CI-V frames: build, decode (echo vs reply, BCD frequency, mode, PTT), convert
rotator_build / rotator_parse	GS-232 rotator commands (read, move, stop, speed) and position replies
clear_buffer / status	Housekeeping; status shows every open port with control-line states

Ports are opened by name ("rig", "rotator"); tools default to the most recently used one. Each connection has a terminal mode: dumb (raw bytes, the default), ansi (colours and escape sequences stripped, CR/backspace overwrites applied, used by the console presets), or xterm/vt100 (a real screen you can read with screen; needs pip install 'serial-console-mcp[screen]', included in the installers). The receive buffer is capped at 4 MB per port; if a device streams for hours unread, the oldest bytes are dropped and status says how many.

Environment variables

Variable	Effect
SERIAL_CONSOLE_READ_ONLY=1	Refuse writes except read-style commands (show, ID;, CI-V reads) and refuse control-line changes
SERIAL_CONSOLE_ALLOW=<regex>	Override the read-only allowlist
SERIAL_CONSOLE_IDLE_MINUTES=15	Auto-close a port idle that long (default: never)

Set them in the server's entry in claude_desktop_config.json under "env".

Installing

1. Download the installer for your computer from the Releases page (the .exe on Windows, or the .pkg on a Mac) and click through it like any normal program. It sets everything up for you. The installers are unsigned for now, so expect a Gatekeeper / SmartScreen warning.
2. Completely quit Claude Desktop — not just closing the window. On Windows, right-click the Claude icon near the clock and choose Quit. On a Mac, press ⌘Q or choose Claude → Quit.
3. Open Claude Desktop again.
4. In a new chat, type: "What serial ports do you see?" If Claude lists your ports, you're done.

That's the whole thing. There's no separate program to keep open and nothing to configure by hand.

Installing from PyPI

If you already have Python 3.10+ and uv or pipx, you don't need the installer:

uvx serial-console-mcp --version                                   # fetches and runs it
uvx serial-console-mcp configure --command uvx --arg serial-console-mcp

or

pipx install serial-console-mcp
serial-console-mcp configure --command "$(which serial-console-mcp)"

configure writes a serial-console entry into claude_desktop_config.json (merging with whatever is already there and backing the old file up first). Quit and reopen Claude Desktop. serial-console-mcp configure --remove undoes it. Any other MCP client can launch the same command over stdio.

Installing from source (developers)

git clone https://github.com/sbrunner-atx/serial-console-mcp.git
cd serial-console-mcp
uv sync                       # or: python3 -m venv .venv && . .venv/bin/activate && pip install -e . pytest
uv run pytest                 # fake serial port, no hardware needed
uv run serial-console-mcp configure --command "$PWD/.venv/bin/serial-console-mcp"

The package lives in src/serial_console_mcp/: server.py is the MCP server, configure.py the Claude Desktop registrar. See BUILD.md for the installers.

Using it

Plain-English requests work. Some examples:

• "List my serial ports."
• "Connect to the console on /dev/cu.usbserial-10 at 9600 baud."
• "Connect to /dev/cu.BLTH at 38400, 8 data bits, no parity, 1 stop bit, XON/XOFF flow control."
• "Connect to the Kenwood with the kenwood-cat preset and call it rig; connect the rotator on the other port."
• "Log in as admin and run show version" (one expect call: return, login, password, command).
• "What baud rate is this thing?" (detect_baud).
• "Key the rig for two seconds" (pulse_line("RTS", 2000), after you confirm).
• "Ask the IC-7300 for its frequency" (civ_build, send_hex, read_available, civ_parse).
• "What is the TS-590 tuned to?" (query_text("FA;"), cat_parse).
• "Turn the rotator to 45 degrees and confirm" (rotator_build, query_text, rotator_parse).
• "Record this console session to a file."
• "Hit Ctrl-C, that ping is still running." (send_keys)
• "Open the BIOS console at 115200 and show me the screen; go down two and press Enter." (screen-console preset, screen, send_keys)
• "Reconnect to the same port as last time." (it remembers)
• "Send a return, then read until the login prompt."
• "Log in as admin and run show interfaces terse, then show me all of it."
• "Just read whatever the device is printing right now."
• "Disconnect when you're done."

For a router/switch console, tell Claude the prompt it should wait for (often # for enable mode or > for user mode) and it will read until it sees it. For an Icom radio (CI-V), tell Claude — it can send the hex commands those radios expect.

If something doesn't work

"No serial ports found."

• Is the device turned on?
• Is the USB cable a real data cable, not a charge-only one? (A very common gotcha.)
• On Windows, open Device Manager and look under Ports (COM & LPT). If nothing's there, Windows needs the cable's driver (often FTDI, CP210x, or CH340).

"Could not open the port" / "access denied."

• A serial port can only be used by one program at a time. Close anything else that might be holding it: a terminal (PuTTY/minicom/screen), WSJT-X, your contest logger, the device's own software.

Claude says it can't access serial ports at all.

• Make sure you fully quit and reopened Claude Desktop after installing.
• Start a brand-new chat and ask "What serial ports do you see?" again.

It connected but a command gets no reply.

• Almost always the baud rate is wrong, or the line ending is wrong for your gear. Most Unix-style consoles want a plain newline (LF); most rigs want a carriage return (CR). Ask Claude to send a return first to draw a fresh prompt.

A word on safety

These tools send exactly what you (through Claude) ask them to send, to whatever device is on the cable. Claude Desktop asks you to approve each tool call, so you see every command before it runs. Read it. A console session on a router or a rig can reconfigure, reboot, or transmit, and this server does not try to guess which commands are dangerous. If something looks wrong, decline it, and keep a real terminal handy for anything you would not want an assistant to type.

License

MIT. See LICENSE.

73!