Vortex Launch Bridge

Vortex Launch Bridge is a Millennium plugin that coordinates Steam launches with Vortex-managed profiles. When you start an eligible game, it lets you activate a Vortex profile first, continue the original Steam launch, or cancel.

Features

• Detects Vortex and reads its supported game/profile state without editing it.
• Warms a background cache at startup and safely refreshes Vortex profile state on every supported Steam PLAY request.
• Uses the game's Steam name and profile count in a native, theme-aware Steam confirmation dialog.
• Activates a selected Vortex profile in Vortex's minimized background mode and waits for deployment confirmation before starting the configured target.
• Includes an explicit, backup-verified compatibility repair for Vortex child processes that otherwise create visible console windows.
• Preserves the exact intercepted Steam launch request when you choose Continue launching with Steam...
• Supports optional remembered choices, preferred profiles, custom executables, custom arguments, and exact Steam AppID-to-Vortex game mappings.
• Fails open before interception whenever eligibility cannot be established safely.
• Keeps settings and diagnostic data local and redacts paths and launch arguments from normal logs.

Important

Continue launching with Steam... is not a "vanilla mode." It replays Steam's original launch request, but it does not remove or change anything Vortex may already have deployed.

Requirements

• Windows 10 or Windows 11
• Desktop Steam
• Millennium
• Vortex

The current local validation environment uses Millennium 3.3.1 and Vortex 2.4.2.

Installation

Millennium plugin catalog

Once the plugin is listed in the Steam Homebrew plugin catalog:

1. Open Steam > Millennium Settings > Plugins.
2. Choose Install a plugin.
3. Enter the plugin ID <Eventual_Steambrew_ID_Here> and install it.
4. Restart Steam when prompted.

Direct GitHub installer

For a direct installation that does not use the Steam Homebrew Plugin Database:

1. Download VortexLaunchBridgeInstaller.exe from the latest GitHub release.
2. Run the installer and confirm the detected Millennium directory.
3. Choose Install/Repair. The installer force-closes Steam and its web helpers first if they are running.
4. Restart Steam and enable the plugin in Steam > Millennium Settings > Plugins if necessary.

The installer downloads an immutable snapshot of the latest main commit, installs the repository's pinned build dependencies in a temporary workspace, runs the production build, validates the runtime package, and atomically installs it under Millennium's user plugins directory. It also provides a Delete action that removes only this plugin's installation folder.

Development installation

Use this method for an unreleased build or local development.

1. Install Node.js 20 and pnpm 10:

   npm install --global pnpm@10.34.5

2. Clone and build the repository:

   git clone https://github.com/WoahItsJeebus/MSVB.git
   Set-Location MSVB
   pnpm install
   pnpm run build

3. Close Steam completely.

4. Open an elevated PowerShell window in the checkout and create a directory junction:

   New-Item `
     -ItemType Junction `
     -Path 'C:\Program Files (x86)\Steam\millennium\plugins\vortex-launch-bridge' `
     -Target (Resolve-Path '.')

   Adjust the Steam path if your Millennium installation is elsewhere. The destination must not already exist.

5. Start Steam. Rebuild and restart Steam after changing plugin code.

The junction links the development checkout directly to Millennium; it does not duplicate the repository.

Using the plugin

Vortex Launch Bridge scans Vortex's read-only state in the background when Steam starts. Launch a Steam game that Vortex manages and that has at least one valid Vortex profile. The prompt offers three actions:

• Launch with Vortex activates a profile, waits for deployment confirmation, and starts the configured launch target.
• Continue launching with Steam... replays the exact Steam request without changing Vortex state.
• Cancel abandons the intercepted request.

With Vortex closed, each supported PLAY request performs a fresh read-only profile query before the prompt is built, so newly added profiles appear without restarting Steam. If Vortex is already running, the bridge retains its last safe snapshot because Vortex does not reliably service that startup query as a second instance.

Only one launch flow is kept at a time. Pressing PLAY again immediately closes and cancels the older prompt or pending check, then handles the newest request; there is no post-cancel cooldown.

For the most reliable profile activation, close Vortex before choosing Launch with Vortex. Vortex applies command-line profile selection during a cold start but may ignore those arguments when forwarding them to an already-running instance.

If activation times out, Retry force-closes all running Vortex instances and repeats the same held profile activation as a cold start. Steam remains held until the retried activation is confirmed, continued through Steam, or cancelled.

Settings

Open Steam > Millennium Settings > Plugins > Vortex Launch Bridge to configure:

• whether every eligible launch asks first;
• opt-in remembered launch choices per game;
• diagnostic launch logging;
• the Vortex activation timeout;
• a preferred Vortex profile for each Steam AppID;
• an optional custom executable and arguments after activation;
• Vortex executable detection or an explicit override;
• read-only Vortex and game-matching diagnostics;
• exact Steam AppID-to-Vortex game-ID overrides.

Settings are stored locally at:

%LOCALAPPDATA%\VortexLaunchBridge\settings.json

Troubleshooting

No launch prompt appears

• Confirm the plugin is enabled and Steam was restarted after installation.
• Open the plugin settings and run Detect Vortex and Run read-only probe.
• Confirm Vortex manages the game and has at least one valid profile for it.
• If automatic matching fails, configure an exact Steam AppID-to-Vortex game-ID override.

Vortex activation times out

• Fully exit Vortex, including its notification-area process, and try again.
• Increase the activation timeout in the plugin settings, up to 25 seconds, if deployment normally takes longer.
• Verify the selected profile still exists and deploys successfully from Vortex itself.

A terminal flashes while Vortex starts

Vortex 2.3.0 through 2.4.2 starts its bundled console-subsystem .NET probe, its fsutil dirty query administrator check, and some shell-backed startup tools without Node's windowsHide option. Version 1.0.7 handles this automatically: a cold Vortex process remains suspended until a scoped startup watcher is ready, and only console windows belonging to descendants of that specific Vortex process are hidden. The watcher exits after 30 seconds, does not require administrator access, and does not modify Vortex.

The release ZIP and installed plugin also include an optional compatibility repair. If a Vortex update introduces a console path outside that startup window, fully exit Vortex and run the repair from an administrator PowerShell opened in the plugin directory:

powershell -NoProfile -ExecutionPolicy Bypass -File scripts\patch-vortex-dotnetprobe.ps1

The script validates Vortex's ASAR layout and affected file hashes, removes the command shell from the administrator check, and creates a complete hash-verified archive backup under %LOCALAPPDATA%\VortexLaunchBridge\Backups, inserts the missing option without changing any file size, updates the corresponding integrity hashes, and verifies the result. Vortex's signed probe remains untouched. A later Vortex update may restore the official files; rerun this optional repair only if the automatic guard does not cover a later child launch.

Logs

The backend log is normally written to:

<Steam>\millennium\logs\vortex-launch-bridge_log.log

Millennium frontend output is written to:

<Steam>\logs\webhelper_js.txt

Enable diagnostic launch logging only while investigating a problem. Before sharing logs, review them for information specific to your system.

If the issue persists, open a bug report with the plugin, Millennium, Vortex, and Windows versions plus the smallest relevant log excerpt.

Safety and privacy

The plugin does not:

• edit Vortex's profile or deployment state directly;
• use Vortex state mutation commands;
• scan unrelated drives;
• inject into game processes;
• remove deployed mods when continuing through Steam;
• send telemetry or settings over the network.

The optional terminal-flash compatibility script changes only the exact guarded child-process entries in Vortex's app.asar when the user explicitly runs it and always retains the complete original archive in the local backup directory above.

During a cold Vortex activation, the bridge briefly observes top-level window creation and visibility events. It acts only on console-class windows whose process ancestry reaches the exact Vortex process it just launched, and the watcher terminates after 30 seconds.

Process launches avoid a command shell, custom arguments use bounded parsing, settings are validated before use, and asynchronous work is bounded by explicit timeouts. See Architecture for the design and trust boundaries.

Development

Prerequisites are Node.js 20, pnpm 10, Windows PowerShell, and Lua 5.1 on PATH.

pnpm install
pnpm run build
pnpm test

pnpm test runs the complete launch, activation, settings, parsing, caching, matching, and process-runner regression suite. If backend/util/process_shell.cs changes, rebuild its committed Windows-subsystem helper with:

pnpm run build:process-shell
pnpm test

Additional references:

• Architecture and safety boundaries
• Testing guide
• Release checklist
• Detailed implementation findings
• Changelog

Contributing

Bug reports and focused pull requests are welcome. Read CONTRIBUTING.md before submitting changes. Please report security-sensitive issues according to SECURITY.md.

License

Vortex Launch Bridge is available under the MIT License.

Steam, Valve, Nexus Mods, and Vortex are trademarks of their respective owners. This independent project is not affiliated with or endorsed by Valve Corporation or Nexus Mods.