The Stintsmith Companion is a small tray daemon that lives next to Le Mans Ultimate on your Windows machine. It is not a sim-racing tool you tab into between sessions. You install it once, pair it once, and then ignore it. From that point on, every session you finish ends up in your Pit Wall on the phone, and every session you run live becomes available to the team strategist in the browser.
It ships as a single signed .msi installer. The runtime is one Rust binary wrapped in Tauri 2 — no window opens, no Electron tax. On every Windows login it brings itself back up and parks in the system tray as a small Stintsmith mark; that icon is the only surface you ever need.
System requirements
Windows 10 or 11, 64-bit. Le Mans Ultimate installed and run at least once so the user-data folders exist. About 80 MB on disk. macOS and Linux are not supported and are not on the roadmap; LMU is a Windows-only title, so a cross-platform Companion would have nothing to watch.
The Companion talks to the portal over HTTPS and a single outbound WebSocket. If your rig sits behind a corporate firewall, allow stintsmith.com on 443. No inbound port needs to open. The daemon never opens a listening socket of its own.
Install
Grab the latest Stintsmith Companion.msi from Settings → Companion inside the portal — the page hosts the current signed build and the SHA-256 next to it, so you can verify the download against what the portal served you. Double-click the installer. Windows SmartScreen will recognise the signature; if you see a generic blue prompt instead, you downloaded an older build — replace it and try again.
The installer drops the binary under %LOCALAPPDATA%\Programs\Stintsmith\Companion, registers an auto-start entry for your user, and launches the daemon. A balloon notification appears within a few seconds: Click to pair this device with Stintsmith. Follow it — pairing is the next article. Until you pair, the daemon does nothing else.
What it captures
Two things, and only those two. Finished sessions — when LMU writes the .duckdb, .csv, and results .xml at the end of a session, the Companion picks them up from Documents\Le Mans Ultimate\UserData\Log\Telemetry\, repacks the DuckDB into Parquet locally, signs the upload with your device’s HMAC key, and posts it to the portal. The find-time loop runs end-to-end without your input.
And live race data — while LMU is actually in a session, the Companion reads the rF2 shared-memory buffers at 60 Hz for your car and 5 Hz for the full field, and streams them to the portal so the live stint planner has something to react to. The first time it tries to read shared memory and finds none, it installs the Iron Wolf plugin DLL into your LMU folder; on the next launch, the buffers come up and streaming begins.
Nothing else leaves your machine. The Companion does not read other game folders, browser history, Discord, voice channels, or microphone. The full list of files it touches is in the source under apps/companion/src/watcher.rs; if a path is not in that file, it is not being read.
If something is wrong
The tray icon carries the daemon’s state at a glance — grey with an exclamation badge means unpaired, dimmed means LMU is not running, and a small dot at the corner means a live session is streaming. Open the menu and you will find Open logs folder; the file you want is %LOCALAPPDATA%\Stintsmith\logs\companion.log. Everything the daemon does — file uploads, retries, shared-memory frames, errors — is in there.
The two failures we see most often:
- Antivirus quarantine. An over-aggressive AV will flag a freshly signed binary for a few days after release. Whitelist
%LOCALAPPDATA%\Programs\Stintsmith\Companion\Companion.exeand the installer will run again clean. - LMU stored the telemetry folder somewhere else. If you moved your Documents folder to OneDrive or to another drive, the watcher will not see anything. Set the override path under Tray → Settings → Telemetry folder and restart the daemon.
- The Iron Wolf plugin failed to install. Almost always a permissions problem on the LMU install folder. Run the Companion once as administrator from the tray’s Reinstall plugin action, then drop it back to normal — the permission is only needed for the DLL copy.
If none of that explains it, mail the team at hello@stintsmith.com with the last hundred lines of companion.log attached. The log is local-only — nothing is sent until you send it.