Wsjtx MCP

Name: Wsjtx MCP
Author: sbrunner-atx

by sbrunner-atxversion 0.1.3i★ –iRuns on your computer

Registry nameio.github.sbrunner-atx/wsjtx-mcp

Install

Overview

Description from the maker (original English)

Operate WSJT-X (FT8/FT4/WSPR) from MCP clients over its UDP message protocol.

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

User voiceiNo reviews yetReviews open together with accounts in a later step
Our basic checksi1 of 1 passedChecked from public information; code not scanned yet
UsageiVery new↓ 26/wk · ★ –

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

Connection: Runs on your computer
Transport: stdio
Category: Other

Install

Pick the AI app you use, then copy the settings.

Before you install

Basic checks: 1 of 1 passed
Runs on your computer with your user’s permissions (files, network, apps).
You fill in yourself: WSJTX_CALLSIGN, WSJTX_HOST, WSJTX_PORT, WSJTX_MULTICAST, WSJTX_INSTANCE

You need

PyPIPython’s uv installed (for the uvx command)

Which app do you use?

ClaudeClaude CodeCursorVS CodeChatGPT

Pick your app above. We remember it, so next time the button says “Install in …”.

Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json

{
  "mcpServers": {
    "wsjtx": {
      "command": "uvx",
      "args": [
        "wsjtx-mcp"
      ],
      "env": {
        "WSJTX_CALLSIGN": "your-value",
        "WSJTX_HOST": "your-value",
        "WSJTX_PORT": "your-value",
        "WSJTX_MULTICAST": "your-value",
        "WSJTX_INSTANCE": "your-value"
      }
    }
  }
}

Run this in your terminal

claude mcp add wsjtx --env WSJTX_CALLSIGN=your-value --env WSJTX_HOST=your-value --env WSJTX_PORT=your-value --env WSJTX_MULTICAST=your-value --env WSJTX_INSTANCE=your-value -- uvx wsjtx-mcp

Fill in the empty values before running it.

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "wsjtx": {
      "command": "uvx",
      "args": [
        "wsjtx-mcp"
      ],
      "env": {
        "WSJTX_CALLSIGN": "your-value",
        "WSJTX_HOST": "your-value",
        "WSJTX_PORT": "your-value",
        "WSJTX_MULTICAST": "your-value",
        "WSJTX_INSTANCE": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "wsjtx": {
      "type": "stdio",
      "command": "uvx",
      "args": [
        "wsjtx-mcp"
      ],
      "env": {
        "WSJTX_CALLSIGN": "your-value",
        "WSJTX_HOST": "your-value",
        "WSJTX_PORT": "your-value",
        "WSJTX_MULTICAST": "your-value",
        "WSJTX_INSTANCE": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.

Your choice stays on this device in a cookie; no account needed.

Values you fill in

WSJTX_CALLSIGN env
Operator callsign — the single transmit gate. Blank = receive-only (refuses all transmit-initiating messages).
WSJTX_HOST env
Address to bind/receive WSJT-X UDP broadcasts on. For a remote WSJT-X use 127.0.0.1 with the mcp-host-bridge 'wsjtx' service and set the port to 2238.
WSJTX_PORT env
WSJT-X Settings → Reporting → UDP Server port. Default 2237. Enable 'Accept UDP requests' for control.
WSJTX_MULTICAST env
Optional multicast group to join so multiple UDP consumers can coexist. Blank = unicast.
WSJTX_INSTANCE env
Optional WSJT-X instance Id to target when several broadcast here.

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

Runs on your computer; the tool list appears in your AI app after you install it.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 9, 2026

✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account sbrunner-atx, which owns the repo
… Not checked yet
Still maintained
We have not read this repo from GitHub yet
… Not checked yet
Has a licence
We have not read this repo from GitHub yet
– Not applicable
Endpoint responds
This one runs on your computer; there is no internet endpoint
– Not applicable
Sign-in with OAuth
Runs on your computer and uses local settings instead
… Not checked yet
No hidden instructions in tool descriptions
Runs on your computer; we can only read tool lists from internet endpoints

Compared with others in Otheri

More stars than 0% of the other 18728 servers in this category
Published to the registry more recently than 36% of the other 18728 servers in this category
Basic checks equal to or better than 100% of the other 18728 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is Wsjtx MCP safe?

It passed 1 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

The registry does not list a required key, though some servers ask you to sign in on first use.

Does it run on my computer or in the cloud?

It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).

Is it still maintained?

The GitHub repo last changed –, and the latest version (0.1.3) reached the registry 2 months ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Python (uv) on your computer.

What can I use instead?

In the same category: Spec Driven Development, Remote Desktop Commander, Systemdox

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README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

wsjtx-mcp

An MCP server that controls WSJT-X (FT8/FT4/JT65/MSK144/Q65/WSPR…) from MCP clients such as Claude Desktop and the MCP Inspector.

It is the weak-signal leg of an "operate → log" trio for amateur radio:

[fldigi-mcp](https://github.com/sbrunner-atx/fldigi-mcp) — operate broad digital modes via fldigi (XML-RPC).
[n3fjp-mcp](https://github.com/sbrunner-atx/n3fjp-mcp) — log QSOs to N3FJP (TCP API).
wsjtx-mcp *(this one)* — operate the FT8/FT4 weak-signal world via WSJT-X (UDP message protocol).

⚠️ Experimental (v0.1). Transmit is gated behind your callsign and you keep

the operator in command. Read the Transmit safety section.

How it is different

WSJT-X does not offer a request/response API. It *broadcasts* state over UDP (Status, Decode, QSOLogged, Heartbeat, …) and honours a small set of inbound *control* messages. So this server runs a background UDP listener that continuously parses datagrams and keeps the latest status, a buffer of decodes, and completed QSOs — you read those, and nudge WSJT-X with control messages.

Consequences worth knowing up front:

No dial-frequency control over UDP. You can read the dial frequency from Status, and set mode/sub-mode/Rx DF/T-R period via configure, but QSY is a rig-control concern (Hamlib/CAT or the UI), not this server.
You can start and halt Tx, but cannot toggle "Enable Tx". Transmission is *started* by answering a CQ (reply) or by free_text with send=true, and *stopped* by transmit halt. There is no UDP command for the "Enable Tx", "Auto Seq", "Call 1st", or "Hold Tx Freq" checkboxes — those stay UI settings.
`reply` gives hands-free QSOs only when WSJT-X's "Auto Seq" is on. A reply is equivalent to double-clicking a CQ; with Auto Seq enabled (the usual FT8/FT4 default) WSJT-X then sequences the whole exchange to QSOLogged with no further calls. With Auto Seq *off*, reply starts only the first transmission.
Best for search-and-pounce, weak for RUN. The API is built to *answer* CQs (and only CQ/QRZ decodes), so S&P is fully automatable. It has no clean way to drive a repeating *call-CQ* (RUN) cycle — that needs WSJT-X's own "Enable Tx", or a free_text CQ re-sent each period.

Requirements

WSJT-X 2.1 through 3.x — the UDP message protocol is schema 3 / Qt_5_4 and has been stable across those releases (verified live against WSJT-X 3.0.2).
In WSJT-X: Settings → Reporting → UDP Server
UDP Server = the host running this server (default 127.0.0.1), port `2237`.
Accept UDP requests = ON to allow *control* (it is OFF by default). Observing decodes/status works without it; commanding does not.

Install (Claude Desktop)

Download the wsjtx-mcp.mcpb from the latest release and double-click it, or drag it onto Claude Desktop → Settings → Extensions. Fill in the settings form (callsign, host, port). See docs/INSTALL.md.

Configuration

Variable	Default	Purpose
`WSJTX_HOST`	`127.0.0.1`	UDP address to bind/listen on.
`WSJTX_PORT`	`2237`	WSJT-X UDP Server port.
`WSJTX_CALLSIGN`	_(empty)_	Operator callsign — the single transmit gate. Blank = receive-only.
`WSJTX_MULTICAST`	_(off)_	Optional multicast group to join (coexist with other UDP consumers).
`WSJTX_INSTANCE`	_(auto)_	Target a specific WSJT-X `Id` when several instances broadcast.

Host/port are where this server listens; control replies are sent back to the address each datagram arrived from.

Tools

Tool	Kind	What it does
`status`	observe	Latest `Status` snapshot + listener/instance health.
`diagnostics`	observe	Host/network + bind status + datagram counts + gate state.
`decodes`	observe/nudge	`read` / `drain` (poll new) / `clear_local` / `replay`. The RX plane.
`log`	observe	Buffered completed QSOs (`QSOLogged` + `LoggedADIF`) → feed N3FJP.
`reply`	transmit	Answer a buffered CQ/QRZ decode (auto-sequences the QSO when WSJT-X "Auto Seq" is on).
`free_text`	transmit if `send`	Set the Tx5 free-text message; `send=true` keys the radio.
`transmit`	control	`halt` / `halt_auto` — stop transmitting (UDP can't enable Tx).
`configure`	control	Mode/sub-mode/Rx DF/T-R period/freq-tol/DX call+grid. No dial freq.
`clear`	control	Clear the Band Activity / Rx Frequency windows.
`highlight`	control	Colour or clear a callsign in Band Activity.
`location`	control	Override the session Maidenhead grid.
`switch_config`	control	Switch to a named WSJT-X configuration.
`annotate`	control	Set a Fox/Hound sort-order annotation for a DX call (niche, DXpedition).
`wsjtx_call`	escape hatch	Build & send any message type by name (gate still applies).

Transmit safety

The callsign is the single transmit gate, exactly as in fldigi-mcp. With WSJTX_CALLSIGN blank the server is receive-only: it refuses every transmit-initiating message — reply, free_text with send=true, and any keying message via wsjtx_call. transmit halt, clear, configure, highlight, location, replay, and all reads are always available (they don't put you on the air; halt takes you *off*).

Beyond that gate:

Per-transmit approval comes from the Claude Desktop tool-permission prompt — lean on it for human-in-the-loop control.
WSJT-X's own Tx Watchdog and the Tx Enabled / Transmitting flags (surfaced in status) are extra safety signals.
Operating under Part 97 automatic/remote control is the operator's responsibility: ensure station identification and a control operator who can intervene.

Running alongside other UDP tools

Only one process can normally own UDP 2237 on a host. If JTAlert, GridTracker, or N1MM already consume it, either point WSJT-X's *secondary* UDP server here, use a multicast group (WSJTX_MULTICAST) so several listeners coexist, or run this server on a different host. To reach a WSJT-X on another machine, install the mcp-host-bridge tool (mcp-host-bridge install wsjtx --to ) and set WSJTX_PORT=2238 — sandboxed MCP clients reach only loopback, and the bridge does the LAN hop. See docs/REMOTE-HOST.md.

Development

uv sync

uv run ruff check . uv run pytest

The protocol codec is pure standard library and unit-tested against byte fixtures, so the tests need no running WSJT-X. A smoke_test.py proves a live WSJT-X is reachable receive-only. The field-tested message reference lives in docs/WSJTX-API.md.

Wsjtx MCP

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

Values you fill in

What it can do

Basic checksi

Maker matches the repo

Still maintained

Has a licence

Endpoint responds

Sign-in with OAuth

No hidden instructions in tool descriptions

Compared with others in Otheri

Common questions

Alternatives

Spec Driven Development

Remote Desktop Commander

Systemdox

README from the maker

wsjtx-mcp

How it is different

Requirements

Install (Claude Desktop)

Configuration

Tools

Transmit safety

Running alongside other UDP tools

Development

License