Ask an AI while you play -- without alt-tabbing.
A transparent, always-on-top companion window that composites over your game and lets you ask Google Gemini, Claude, or OpenAI questions in-game. Bring your own provider, attach a screenshot for context, or translate on-screen text -- all without ever leaving the game, and without injecting anything into it.
I built this for myself -- a way to ask an AI for a hint, a build, or a translation while playing, without alt-tabbing to a browser and losing the moment. Responses come from Sage, an in-game advisor drawn in a panel over the running game.
Earlier versions injected a DLL and hooked the game's renderer. That was fragile and looked like the thing anti-cheats flag, so it was dropped entirely. Sage now runs as its own transparent window that Windows composites over the game -- it never injects, never hooks a graphics API, and cannot crash the game.
It's deliberately bring-your-own-AI: Gemini talks to its own free API, while Claude and OpenAI run through your existing CLI subscriptions -- no middleman service, no shared keys. There's no telemetry, no analytics, and no account.
It's a personal tool, not a product -- open source under MIT. No adoption goal and no support guarantees, but issues and PRs are read.
Actively developed personal tool, shipped as tagged Windows releases. It targets borderless / fullscreen-optimized games (effectively all modern single-player titles); genuine legacy exclusive-fullscreen games are out of scope. Treat it as a working tool you can build and run, not a polished consumer app.
Implemented:
- External transparent overlay window -- topmost, click-through when idle, takes focus on demand; toggled with Ctrl+Shift+G. No injection, any graphics API.
- Multi-provider AI -- Gemini (direct API), Claude & OpenAI (through your own
claude/codexCLIs), switchable from an in-panel dropdown that shows only available providers and persists your choice. - Streaming "Sage" replies over a Tauri channel, multi-turn chat, Stop / New chat.
- Screenshot vision (Gemini + Claude) via Windows.Graphics.Capture -- capture the game frame with no injection; skipped for OpenAI (upstream Codex limitation).
- Screen translation (Ctrl+Shift+T) and quick-ask (Ctrl+Shift+A) hotkeys.
- Desktop launcher (Tauri 2 + Svelte 5) -- Steam library discovery, cover art, one-click launch, tray, launch-on-startup, and play-time via an external process watcher.
- In-app Settings: your Gemini key is stored in the Windows Credential Manager (not plaintext), plus CLI detection, a persisted default provider, and launcher toggles.
Not done yet / out of scope:
- OpenAI screenshots -- blocked on an upstream Codex CLI fix.
- Rebindable hotkeys -- the chords are fixed this build (Settings shows them).
- Positioning the panel over the game's specific monitor (it opens centered).
- Offline / local-model translation -- translation currently runs through Gemini.
- Genuine legacy exclusive-fullscreen games -- an external window can't composite over those; borderless / FSO windowed is covered.
- Competitive / kernel-anti-cheat titles are a non-goal.
- A transparent, frameless, always-on-top panel Windows composites over the game -- no DLL, no swapchain hook, works regardless of graphics API.
- Ctrl+Shift+G toggles it; while interactive it takes keyboard focus so your typing doesn't reach the game, then hands focus back on hide.
Sage can talk through Gemini, Claude, or OpenAI -- pick one from the in-panel dropdown (only available providers are shown; the choice persists).
- Gemini -- direct API with a free key (Google AI Studio), entered in Settings and stored in the OS Credential Manager.
- Claude -- your existing Claude Code CLI, no separate key.
- OpenAI -- your existing Codex CLI, no separate key.
The CLIs are spawned directly as subprocesses -- the same pattern documented for headless Claude Code. No OAuth tokens are extracted or shared; each user authenticates their own CLIs. Providers never fall back to one another silently.
Attach the current frame to a question (Gemini / Claude) -- captured via Windows.Graphics.Capture, no injection. Press Ctrl+Shift+T to translate on-screen text through Gemini, or Ctrl+Shift+A to fire a preset question with a screenshot attached.
A Tauri 2 + Svelte 5 GUI for your library: Steam auto-discovery, Steam-CDN cover art, one-click launch, play-time tracking via an external process watcher, tray, launch-on-startup, and an in-app Settings panel (provider key + detection, default provider, hotkey reference, launcher toggles).
| Layer | Choice | Notes |
|---|---|---|
| App | Tauri 2 + Svelte 5 + Tailwind 4 | One process, two windows: library + transparent overlay |
| Capture | windows crate (WinRT) | Windows.Graphics.Capture -> D3D11 -> PNG; foreground-HWND game detection |
| Async / HTTP | tokio + reqwest | Gemini streaming + CLI subprocesses off the UI thread |
| Shared state | parking_lot | Fast mutex for the shared app state |
| Secrets | keyring | Gemini key in the Windows Credential Manager |
| Build | cargo-xwin | MSVC cross-compile from WSL2 |
| Logging | tracing | Structured logs to launcher.log |
- Get a free Gemini key at Google AI Studio -- no billing required. (Or skip it and use your existing Claude / OpenAI CLI.)
- Run
launcher.exe, open Settings -> Providers, and paste your Gemini key (stored in the Windows Credential Manager). Claude / OpenAI are detected automatically if their CLIs are installed. - Play. With a game in the foreground, press Ctrl+Shift+G to open Sage, type a question, and optionally attach the current frame. Ctrl+Shift+T translates on-screen text; Ctrl+Shift+A asks a preset question.
├── Cargo.toml # workspace root
├── crates/
│ └── launcher/ # the whole app (Tauri 2 + Svelte 5)
│ ├── src/ # Svelte frontend (runes): library + overlay UI
│ └── src-tauri/ # Rust backend: overlay window, WGC capture,
│ # in-process AI dispatch, Steam discovery, secrets
├── config.example.toml # optional legacy key fallback (no real key)
└── scripts/build.sh # release build -> release/
Built from WSL2 with cargo-xwin -- no native Visual Studio needed.
rustup target add x86_64-pc-windows-msvc
cargo install cargo-xwin
sudo apt install clang lld llvm
cargo xwin build -p launcher --target x86_64-pc-windows-msvc # debug
./scripts/build.sh # release -> release/Lint + test gates:
cargo xwin clippy -p launcher --target x86_64-pc-windows-msvc -- -D warnings
cargo test -p launcher # pure-logic tests; run on the Linux host- Overlay doesn't appear over the game -- use borderless / fullscreen-windowed mode; a topmost window can't composite over true exclusive fullscreen.
- Claude / OpenAI missing from the dropdown -- their CLIs may still be detecting (especially under WSL); open Settings and press Re-check CLIs.
- Screenshot is black -- some protected/DRM content or minimized windows can't be captured via Windows.Graphics.Capture; try borderless.
- Gemini errors -- "invalid key" re-enter it in Settings; "rate limited" the free tier allows roughly 250 requests/day.
- Can't crash the game. Sage is a separate window, not injected code -- a bug in the companion never takes the game down with it.
- Bring your own AI, no middleman. Gemini talks direct; Claude / OpenAI spawn your own authenticated CLIs. No tokens extracted, no shared service.
- No silent fallback. Providers never switch behind your back -- a failed request fails loudly rather than leaking your prompt to a different vendor.
- Secrets stay secret. The Gemini key lives in the OS Credential Manager, never plaintext; no telemetry or analytics anywhere.
MIT. Release notes live in CHANGELOG.md.
AI Game Companion is a personal tool -- built for my own use, with no telemetry or analytics. It runs as a separate transparent window composited over the game: it does not inject code, read or modify game memory, or touch network traffic or game logic. You are responsible for complying with each AI provider's terms of service. Not chasing adoption, but if it looks useful, you're welcome to try it.