Local broker that lets multiple tools share one Clip Studio Paint Companion Mode connection.

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README.md

CSP Mux

Clip Studio Paint offers exactly one Companion Mode connection, and pairing a second app invalidates the first. CSP Mux scans CSP's QR once, holds that connection, and re-shares it as a proxy QR that up to eight apps can scan.

Use it

In CSP: File > Connect to smartphone (Datei > Mit Smartphone verbinden...). Leave the QR on screen. The menu item is a toggle — selecting it while Companion Mode is on turns it off.
Run CSP Mux.exe. Pick a Connection scope in Settings; it locks while sharing.
Select Scan CSP QR. Wait for status Sharing and the proxy QR.
Point each app at the proxy QR. CSP's QR can be dismissed now.

Window 460x620. Closing hides to the tray; exit from the tray icon.

Connection scope

Scope	Reachable from	Cost
This computer only · 127.0.0.1 (default)	apps on this PC	none
A private IPv4 address	a phone or tablet on that network	one Windows Firewall prompt

Only the picked address is bound; non-private ones are refused.

Hide QR

Hide QR blurs the code in place; the proxy and every connected app keep running. Settings can hide it after the first app connects.

CSP Palette Companion

No QR scan. Sharing on loopback publishes %LOCALAPPDATA%\CSP Suite\mux-session.json, which the Companion connects from — a proxy credential only, never CSP's. Details.

Download

Windows 10/11, 64-bit. Both files are the same app.

Download	Size	You need
`CSP-Mux-<version>-win-x64-needs-dotnet10.exe`	0.9 MB	the latest .NET 10 Desktop Runtime
`CSP-Mux-<version>-win-x64-standalone.exe`	73.8 MB	nothing

Take the small one unless you would rather not install the runtime. Both are unsigned single-file bundles that scanners sometimes flag — Installation has the SHA256SUMS.txt check and the exclusion steps.

Build

.NET 10 SDK, Windows only — Build from source.

Status

Proof of concept, verified against CSP PRO 4.0.10 with a German UI: CSP to Mux to Palette Companion, a 12-colour palette extracted through the proxy. Unproven: other Companion clients, upstream reconnection after CSP drops the socket, load, and per-client permissions — every app has the same capabilities. Companion Mode is reverse-engineered and breaks if CSP changes its protocol.