Merge pull request 'feat: Steam game & library detection (M6) — 0.8.0' (#2) from feat/m6-steam-detection into main

Reviewed-on: #2

CHANGELOG.md

@@ -5,6 +5,108 @@ All notable changes to RigDoctor are recorded here. Format follows
 (`MAJOR.MINOR.PATCH`, pre-1.0). `__version__` and `pyproject.toml` must match the git
 release tag (so the auto-updater, D18, can compare versions).
 
+## [0.8.0] - 2026-05-22
+### Added
+- **Gaming environment checks (M6) — Steam game detection.** RigDoctor now finds your Steam
+  libraries (across multiple drives, via `libraryfolders.vdf`) and the games installed in each
+  (parsing `appmanifest_*.acf` — stdlib only, no Steam tooling needed). Runtimes, Proton builds,
+  and redistributables are filtered out.
+  - **Opt-in libraries:** detected libraries are listed with a per-library game count; you check
+    the ones to scan. Nothing is scanned until you pick a library.
+  - **Background scan on every launch:** the GUI rescans the selected libraries in the background
+    when it opens and flags games installed since the last scan with a **NEW** badge plus a count
+    on the **Games** sidebar item (cleared when you view the page). Results are cached
+    (`~/.local/state/rigdoctor/games.json`) so the list shows instantly.
+  - **CLI:** `rigdoctor games` lists detected games; `rigdoctor games libraries
+    [--enable PATH | --disable PATH | --all]` lists/selects libraries (headless-complete, D17).
+- Config now supports list values (TOML arrays); `steam_libraries` records the selected libraries.
+
+## [0.7.3] - 2026-05-21
+### Fixed
+- Shared terminal now has **scrollback** — large output (e.g. `ls -la`) can be scrolled up to
+  read; it keeps a history buffer and only auto-scrolls to the bottom when you're already there.
+
+## [0.7.2] - 2026-05-21
+### Changed
+- Removed the GUI **Inventory** tab — use the CLI `rigdoctor inventory` instead. (Inventory is
+  still collected for the relay guest view, so a remote helper still sees the host's hardware.)
+### Fixed
+- Shared terminal caret now sits at the real cursor position (row **and** column) instead of
+  the start of the line.
+
+## [0.7.1] - 2026-05-21
+### Fixed
+- Shared terminal: a guest who joined **after** the host enabled the terminal stayed read-only.
+  The host now re-sends the terminal state when a guest joins, so the terminal is available.
+- Inventory page no longer jumps back to the top when it refreshes (e.g. when elevated data
+  arrives) — scroll position is preserved and unchanged data isn't re-rendered.
+- Shared terminal now follows the cursor to the bottom as output arrives (e.g. `ls -la`),
+  instead of staying scrolled up.
+
+## [0.7.0] - 2026-05-21
+### Added
+- **Shared terminal (M12, Tier 3)**: when the host enables it, the session shares a real **PTY**
+  shell — the guest gets an interactive terminal (vim, top, tab-completion, Ctrl-C) running on
+  the host as the host's user. The host **reads along** live and can type too, e.g. a `sudo`
+  password — which stays local and is never sent to the guest. Off by default, host-consented.
+  The guest also pulls the host's inventory on join.
+### Fixed
+- **Input contrast**: all form controls (text fields, spin boxes, combo boxes, terminals) now
+  use the dark theme with readable text (Fusion defaulted them to light-on-light).
+
+## [0.6.0] - 2026-05-21
+### Added
+- **Session sharing over the relay (M12)**: a **Share** tab — *Start shared session* (host)
+  hands you a short code and streams a read-only live view; *Enter share code* (guest) joins
+  someone else's session and views their sensors/health/inventory. Both connect outbound over
+  WebSocket to the relay (`relay_url`, default `wss://rigdoctor.jesseyvanofferen.com`), gated
+  by your Gitea access token — no port forwarding. Read-only.
+
+## [0.5.0] - 2026-05-21
+### Added
+- **Session sharing (M12, Tier 2)**: `rigdoctor share serve` starts a **read-only** live view
+  (sensors auto-refresh + health report + inventory) over a local HTTP server, gated by a
+  random share token. Bind to localhost for local testing, or to all interfaces behind a
+  user-chosen tunnel (Tailscale/cloudflared/SSH) for remote help. No actions, no terminal.
+  (Tier 1 export and Tier 3 gated terminal still to come — D16.)
+
+## [0.4.1] - 2026-05-21
+### Fixed
+- Checkbox contrast: a checked checkbox is now a clear accent-filled box with a checkmark
+  (was hard to tell checked from unchecked on the dark theme).
+
+## [0.4.0] - 2026-05-21
+### Added
+- **Alerts (M8)**: desktop notifications (via `notify-send`) for **overheat** (GPU/CPU past a
+  threshold), **GPU-lost** (nvidia-smi timeout), and a **new version available** (fired once
+  per version). Edge-triggered with a cooldown so it doesn't spam. Degrades gracefully if
+  `notify-send` isn't installed.
+- **Notifications page**: configure alerts (enable/disable, GPU/CPU temperature thresholds)
+  with a "Send test" button; changes apply live and persist to `config.toml`.
+- **App icon**: ships a RigDoctor icon and shows it in the dock/launcher. The GUI
+  **self-registers** the icon + `.desktop` on launch (and sets the Wayland app-id), so a
+  self-update + relaunch picks it up — no need to re-run the installer.
+
+## [0.3.2] - 2026-05-21
+### Changed
+- Replaced the per-page "Run with admin" buttons with a **single password prompt at launch**
+  (`pkexec`): the GUI collects root-only data (SMART + dmidecode board/BIOS/RAM) once and
+  caches it for the session, so Health and Inventory always show the full picture. Falls back
+  to non-root if cancelled/unavailable; disable via `elevate_on_launch = false`.
+
+## [0.3.1] - 2026-05-21
+### Fixed
+- Changelog/release notes now **render Markdown** instead of showing raw `#`/`**` markup —
+  the in-app changelog uses `QTextEdit.setMarkdown()` and the update prompt renders notes as
+  rich text (closes #1).
+
+## [0.3.0] - 2026-05-21
+### Added
+- **System inventory (M5)**: CPU, GPU (model/driver/VBIOS/VRAM/PCIe), motherboard/BIOS, RAM
+  (total + modules), storage, kernel, and display server. CLI `rigdoctor inventory`
+  (`--json` / `--markdown` / `--output`) and a GUI **Inventory** tab with Copy-as-Markdown,
+  Save, and "Run with admin" (for `dmidecode` board/BIOS/RAM details). Fills the last GUI tab.
+
 ## [0.2.0] - 2026-05-21
 ### Added
 - **"Check for updates" button** in the sidebar — force an immediate version check instead of

docs/MODULES.md

@@ -12,13 +12,13 @@ Status: ⬜ not started · 🟦 designing · 🟨 in progress · ✅ done
 | M3 | Crash-capture logger | Essential | none (opt: smartmontools) | all (NVIDIA first) | P0 | 🟨 |
 | M4 | Health report (log scan) | Essential | none (opt: smartmontools) | all (NVIDIA first) | P0 | 🟨 |
 | M2 | Live monitor (TUI) | Monitoring | none (stdlib curses) | all | P1 | ⬜ |
-| M8 | Alerting | Monitoring | libnotify (opt) | all | P2 | ⬜ |
+| M8 | Alerting | Monitoring | libnotify (opt) | all | P2 | 🟨 |
-| M5 | System inventory | Diagnostics | none (opt: lm-sensors, dmidecode) | all | P1 | ⬜ |
+| M5 | System inventory | Diagnostics | none (opt: lm-sensors, dmidecode) | all | P1 | 🟨 |
-| M6 | Gaming env checks | Diagnostics | none | all | P2 | ⬜ |
+| M6 | Gaming env checks | Diagnostics | none | all | P2 | 🟨 |
 | M10 | Desktop GUI | Desktop UI | **python3-pyside6** | all | P2 | 🟨 |
 | M11 | Tray / menu-bar applet | Desktop UI | **python3-pyside6** (+ AppIndicator on GNOME) | all | P2 | ⬜ |
 | M9 | Installer | (meta) | none | all | P1 | 🟨 |
-| M12 | Session sharing / remote assist | Sharing | none (Tier 3: tmate/sshx) | all | P3 | ⬜ |
+| M12 | Session sharing / remote assist | Sharing | none (Tier 3: tmate/sshx) | all | P3 | 🟨 |
 | M13 | Auto-update | (core) | none (stdlib; user-local file swap) | all | P3 | 🟨 |
 | ~~M7~~ | ~~Stress / repro~~ | — | — | — | — | ❌ dropped (D7) |
 
@@ -41,7 +41,15 @@ Status: ⬜ not started · 🟦 designing · 🟨 in progress · ✅ done
   (text/JSON) + GUI Health tab. GPU-firmware verification deferred.
 - **M2 Live monitor** — depends on M1; the terminal "HWMonitor for Linux" face. Stdlib-only.
 - **M5 / M6 Diagnostics** — inventory export + gaming-env checks; M6 flags risky settings and
-  suggests the fix command but does not apply it (D9).
+  suggests the fix command but does not apply it (D9). *M6 implemented (Steam detection first —
+  the D12 "pick a game" foundation):* discovers Steam installs + all library folders
+  (`libraryfolders.vdf`, multi-drive) and the games in each (`appmanifest_*.acf`), filtering
+  runtimes/Proton/redistributables — stdlib only. **Libraries are opt-in** (`steam_libraries`
+  config); the GUI **Games** page lists them with per-library counts and rescans in the
+  background on every launch, badging games installed since the last scan (cached in
+  `state/games.json`). CLI: `rigdoctor games` / `games libraries [--enable|--disable|--all]`.
+  *Pending:* the env-check probes (CPU governor, GPU persistence, GameMode/MangoHud, swappiness,
+  hugepages, mitigations, PCIe ASPM) and non-Steam launchers (Lutris/Heroic).
 - **M8 Alerting** — threshold/event notifications; integrates with the tray applet (M11).
 - **M10 Desktop GUI** — PySide6 graphical front-end over the core engine (dashboard, log
   browser, report viewer, logger controls). Optional; adds the Qt dependency. *Bootstrapped

docs/ROADMAP.md

@@ -27,7 +27,11 @@ Ubuntu + NVIDIA first; `.deb` distribution (see `DECISIONS.md`).
 
 ## Phase 3 — Diagnostics breadth
 - [ ] M5 system inventory + exportable report
-- [ ] M6 gaming environment checks (suggest-only)
+- [~] M6 gaming environment checks (suggest-only) — *Steam game/library detection done*
+      (multi-library `libraryfolders.vdf` discovery + `appmanifest` scan, opt-in libraries,
+      launch-time background rescan with new-game badge; CLI `rigdoctor games`, GUI Games page).
+      This is also the D12 "pick a game" foundation. *Pending:* the env-check probes (governor,
+      GPU persistence, GameMode/MangoHud, swappiness, hugepages, mitigations, PCIe ASPM).
 - [ ] SMART integration (smartmontools if present)
 
 ## Phase 4 — Desktop UI & installer
@@ -58,10 +62,10 @@ Ubuntu + NVIDIA first; `.deb` distribution (see `DECISIONS.md`).
 Escalating ladder, built in order:
 - [ ] Tier 1: `share export` — diagnostic bundle (inventory + recent log + report); B opens
       it in RigDoctor. One-way, safest.
-- [ ] Tier 2: live read-only view (local server + user-chosen tunnel: Tailscale/cloudflared/
+- [x] Tier 2: live read-only view — `rigdoctor share serve` (stdlib HTTP, token-gated:
-      SSH; no hosted relay), token-gated, A approves, revocable.
+      sensors + health + inventory). Remote = user-chosen tunnel; GUI controls still to add.
-- [ ] Tier 3: gated interactive terminal (wrap tmate/sshx; read-only default, read-write on
+- [x] Tier 3: host-consented interactive terminal — a real PTY shell shared over the relay
-      explicit consent), with session audit log.
+      (own `pty`, pyte-rendered guest), off by default; host reads along + can type (sudo).
 
 > **Out of scope:** stress/repro module (D7); multi-distro support and packaging beyond
 > Ubuntu/apt + `.deb` (D15) — a thin seam is kept but not built out.

install.sh

@@ -16,7 +16,8 @@ SCRIPT_DIR=$(CDPATH= cd -- "$(dirname -- "$0")" && pwd)
 uninstall() {
     echo "Removing RigDoctor user-local install…"
     rm -rf "$VENV"
-    rm -f "$BIN_DIR/rigdoctor" "$BIN_DIR/rigdoctor-gui" "$DESKTOP_FILE"
+    rm -f "$BIN_DIR/rigdoctor" "$BIN_DIR/rigdoctor-gui" "$DESKTOP_FILE" \
+          "$DATA_HOME/icons/hicolor/scalable/apps/rigdoctor.svg"
     echo "Done. (Config and logs under ~/.config/rigdoctor and ~/.local/share/rigdoctor were kept.)"
 }
 
@@ -81,6 +82,17 @@ mkdir -p "$BIN_DIR"
 ln -sf "$VENV/bin/rigdoctor" "$BIN_DIR/rigdoctor"
 ln -sf "$VENV/bin/rigdoctor-gui" "$BIN_DIR/rigdoctor-gui"
 
+# Install the app icon (for the dock/launcher); fall back to a stock icon.
+ICON_NAME=utilities-system-monitor
+ICON_SRC=$("$VENV/bin/python" -c "import os, rigdoctor.gui as g; print(os.path.join(os.path.dirname(g.__file__), 'assets', 'rigdoctor.svg'))" 2>/dev/null || true)
+if [ -n "$ICON_SRC" ] && [ -f "$ICON_SRC" ]; then
+    ICON_DST="$DATA_HOME/icons/hicolor/scalable/apps/rigdoctor.svg"
+    mkdir -p "$(dirname "$ICON_DST")"
+    cp "$ICON_SRC" "$ICON_DST"
+    ICON_NAME=rigdoctor
+    command -v gtk-update-icon-cache >/dev/null 2>&1 && gtk-update-icon-cache -qtf "$DATA_HOME/icons/hicolor" 2>/dev/null || true
+fi
+
 mkdir -p "$DESKTOP_DIR"
 cat > "$DESKTOP_FILE" <<EOF
 [Desktop Entry]
@@ -88,10 +100,12 @@ Type=Application
 Name=RigDoctor
 Comment=Hardware monitoring & crash diagnostics for Linux gamers
 Exec=$VENV/bin/rigdoctor-gui
-Icon=utilities-system-monitor
+Icon=$ICON_NAME
 Terminal=false
 Categories=System;Monitor;Utility;
+StartupWMClass=rigdoctor
 EOF
+command -v update-desktop-database >/dev/null 2>&1 && update-desktop-database "$DESKTOP_DIR" 2>/dev/null || true
 
 echo
 echo "RigDoctor $("$VENV/bin/rigdoctor" --version 2>/dev/null | awk '{print $2}') installed."

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "rigdoctor"
-version = "0.2.0"
+version = "0.8.0"
 description = "Modular hardware monitoring & crash diagnostics for Linux gamers."
 readme = "README.md"
 requires-python = ">=3.11"
@@ -13,7 +13,7 @@ requires-python = ">=3.11"
 dependencies = []
 
 [project.optional-dependencies]
-gui = ["PySide6"]
+gui = ["PySide6", "pyte"]
 
 [project.scripts]
 rigdoctor = "rigdoctor.cli:main"
@@ -21,3 +21,6 @@ rigdoctor-gui = "rigdoctor.gui.app:main"
 
 [tool.setuptools.packages.find]
 where = ["src"]
+
+[tool.setuptools.package-data]
+rigdoctor = ["gui/assets/*.svg"]

src/rigdoctor/__init__.py

@@ -1,3 +1,3 @@
 """RigDoctor — modular hardware monitoring & crash diagnostics for Linux gamers."""
 
-__version__ = "0.2.0"
+__version__ = "0.8.0"

src/rigdoctor/cli.py

@@ -295,6 +295,42 @@ def cmd_uninstall(args) -> int:
     return 0
 
 
+def cmd_share_serve(args) -> int:
+    from .core import share
+
+    return share.serve(host=args.host, port=args.port)
+
+
+def cmd_collect_priv(args) -> int:
+    """Internal: emit root-only data (SMART + dmidecode) as JSON, run via pkexec at launch."""
+    from dataclasses import asdict
+
+    from .core.health import check_smart
+    from .core.inventory import _dmidecode
+
+    data = {"smart": [asdict(f) for f in check_smart()], "dmidecode": _dmidecode()}
+    print(json.dumps(data))
+    return 0
+
+
+def cmd_inventory(args) -> int:
+    from .core import inventory
+
+    sections = inventory.collect()
+    if args.json:
+        text = inventory.render_json(sections)
+    elif args.markdown:
+        text = inventory.render_markdown(sections)
+    else:
+        text = inventory.render_text(sections)
+    if args.output:
+        Path(args.output).write_text(text)
+        print(f"Wrote {args.output}")
+    else:
+        print(text)
+    return 0
+
+
 def cmd_report(args) -> int:
     from dataclasses import asdict
 
@@ -309,6 +345,73 @@ def cmd_report(args) -> int:
     return 0
 
 
+def cmd_games(args) -> int:
+    from .core import steam
+
+    selected = steam.selected_library_paths()
+    if not selected:
+        print("No Steam libraries selected to scan.")
+        print("  See them with:   rigdoctor games libraries")
+        print("  Then enable one: rigdoctor games libraries --enable <path>  (or --all)")
+        return 1
+    result = steam.rescan()
+    if args.json:
+        from dataclasses import asdict
+
+        print(json.dumps({
+            "scanned_at": result.scanned_at,
+            "new_appids": result.new_appids,
+            "games": [asdict(g) for g in result.games],
+        }, indent=2, ensure_ascii=False))
+        return 0
+    if not result.games:
+        print("No games found in the selected Steam libraries.")
+        return 0
+    new = set(result.new_appids)
+    print(f"{len(result.games)} game(s) across {len(selected)} librar(y/ies):\n")
+    for g in result.games:
+        flag = " NEW" if g.appid in new else ""
+        print(f"  {g.name:<48} {steam.human_size(g.size_bytes):>9}{flag}")
+    if new:
+        print(f"\n{len(new)} newly-installed since the last scan.")
+    return 0
+
+
+def cmd_games_libraries(args) -> int:
+    from .core import steam
+
+    discovered = steam.discover_libraries()
+    selected = {os.path.realpath(p) for p in steam.selected_library_paths()}
+
+    # --all / --enable / --disable adjust the selection, then we list the result.
+    if args.all or args.enable or args.disable:
+        if args.all:
+            selected = {lib.path for lib in discovered}
+        for raw in args.enable or []:
+            selected.add(os.path.realpath(os.path.expanduser(raw)))
+        for raw in args.disable or []:
+            selected.discard(os.path.realpath(os.path.expanduser(raw)))
+        config.update_config(steam_libraries=sorted(selected))
+
+    if not discovered:
+        print("No Steam libraries detected (is Steam installed?).")
+        return 1
+    if args.json:
+        print(json.dumps([
+            {"path": lib.path, "label": lib.label, "selected": lib.path in selected,
+             "games": len(steam.scan_library(lib.path))}
+            for lib in discovered
+        ], indent=2, ensure_ascii=False))
+        return 0
+    print("Steam libraries (checked = scanned for games):\n")
+    for lib in discovered:
+        mark = "x" if lib.path in selected else " "
+        count = len(steam.scan_library(lib.path))
+        label = f"  [{lib.label}]" if lib.label else ""
+        print(f"  [{mark}] {lib.path}{label}  ({count} games)")
+    return 0
+
+
 def build_parser() -> argparse.ArgumentParser:
     p = argparse.ArgumentParser(
         prog="rigdoctor",
@@ -371,6 +474,33 @@ def build_parser() -> argparse.ArgumentParser:
     rep = sub.add_parser("report", help="health report (M4): scan logs/SMART/driver for issues")
     rep.add_argument("--json", action="store_true", help="output JSON instead of text")
     rep.set_defaults(func=cmd_report)
+
+    cp = sub.add_parser("collect-priv", help=argparse.SUPPRESS)  # internal: run via pkexec
+    cp.set_defaults(func=cmd_collect_priv)
+
+    share_p = sub.add_parser("share", help="session sharing (M12)")
+    share_sub = share_p.add_subparsers(dest="share_cmd", required=True)
+    serve_p = share_sub.add_parser("serve", help="serve a read-only live view (token-gated)")
+    serve_p.add_argument("--host", default="127.0.0.1", help="bind address (use 0.0.0.0 + a tunnel for remote)")
+    serve_p.add_argument("--port", type=int, default=8765, help="port")
+    serve_p.set_defaults(func=cmd_share_serve)
+
+    inv = sub.add_parser("inventory", help="system inventory (M5): export hardware/OS details")
+    inv.add_argument("--json", action="store_true", help="output JSON")
+    inv.add_argument("--markdown", action="store_true", help="output Markdown (for forum/bug reports)")
+    inv.add_argument("-o", "--output", default=None, help="write to a file instead of stdout")
+    inv.set_defaults(func=cmd_inventory)
+
+    games_p = sub.add_parser("games", help="Steam game & library detection (M6)")
+    games_p.add_argument("--json", action="store_true", help="output JSON")
+    games_p.set_defaults(func=cmd_games)
+    games_sub = games_p.add_subparsers(dest="games_cmd")
+    lib_p = games_sub.add_parser("libraries", help="list/select Steam libraries to scan")
+    lib_p.add_argument("--enable", action="append", metavar="PATH", help="scan this library (repeatable)")
+    lib_p.add_argument("--disable", action="append", metavar="PATH", help="stop scanning this library (repeatable)")
+    lib_p.add_argument("--all", action="store_true", help="scan all detected libraries")
+    lib_p.add_argument("--json", action="store_true", help="output JSON")
+    lib_p.set_defaults(func=cmd_games_libraries)
     return p
 
 

src/rigdoctor/config.py

@@ -27,6 +27,10 @@ STATUS_FILE = STATE_DIR / "recorder.json"
 PID_FILE = STATE_DIR / "recorder.pid"
 SPAWN_LOG = STATE_DIR / "recorder.out"
 
+# Gaming environment / game detection (M6) — cached Steam game scan (mutable state,
+# not config: refreshed by the background scan on every launch).
+GAMES_FILE = STATE_DIR / "games.json"
+
 # Update access token (M13) — gates updates to Gitea account holders (D18).
 # Stored in the OS keyring (Secret Service / GNOME Keyring) via `secret-tool` when
 # available — encrypted at rest, unlocked with the login session — else a 0600 file.
@@ -138,6 +142,12 @@ DEFAULTS: dict = {
     "log_max_bytes": 20_000_000,  # rotate a log segment past this size
     "log_backups": 10,            # keep this many rotated segments (bounds disk use)
     "update_check_minutes": 30,   # re-check for updates this often while running (0 = off)
+    "elevate_on_launch": True,    # GUI asks for the password once at launch (SMART/dmidecode)
+    "alerts_enabled": True,       # desktop notifications on overheat / GPU-lost / new version
+    "gpu_temp_alert": 90.0,       # °C — alert when GPU reaches this
+    "cpu_temp_alert": 95.0,       # °C — alert when CPU reaches this
+    "relay_url": "wss://rigdoctor.jesseyvanofferen.com",  # session-sharing relay (M12)
+    "steam_libraries": [],        # Steam library paths to scan for games (M6); empty = none picked yet
 }
 
 
@@ -153,3 +163,29 @@ def load_config() -> dict:
     except Exception:
         pass
     return cfg
+
+
+def _toml_value(value) -> str:
+    if isinstance(value, bool):
+        return "true" if value else "false"
+    if isinstance(value, (int, float)):
+        return repr(value)
+    if isinstance(value, (list, tuple)):
+        return "[" + ", ".join(_toml_value(v) for v in value) + "]"
+    return '"' + str(value).replace("\\", "\\\\").replace('"', '\\"') + '"'
+
+
+def save_config(values: dict) -> None:
+    """Write a flat config.toml (stdlib has no TOML writer)."""
+    CONFIG_DIR.mkdir(parents=True, exist_ok=True)
+    lines = ["# RigDoctor config — edit in the app (Notifications) or here."]
+    lines += [f"{key} = {_toml_value(value)}" for key, value in values.items()]
+    CONFIG_FILE.write_text("\n".join(lines) + "\n")
+
+
+def update_config(**changes) -> dict:
+    """Merge changes into the current effective config and persist them."""
+    cfg = load_config()
+    cfg.update(changes)
+    save_config(cfg)
+    return cfg

src/rigdoctor/core/alerts.py

@@ -0,0 +1,91 @@
+"""Desktop alerts (M8): notify on overheat / GPU-lost / new version via notify-send.
+
+Edge-triggered: an alert fires when a condition becomes true (not every sample), and
+can fire again only after it has cleared and a cooldown has passed — so a hot GPU or a
+1-Hz sample loop doesn't spam notifications. Degrades to a no-op if notify-send is absent.
+"""
+
+from __future__ import annotations
+
+import shutil
+import subprocess
+import time
+
+from .sample import Sample
+
+APP_NAME = "RigDoctor"
+_ICON = "utilities-system-monitor"
+
+
+def available() -> bool:
+    return shutil.which("notify-send") is not None
+
+
+def notify(title: str, message: str, urgency: str = "normal") -> bool:
+    """Send a desktop notification (best-effort). urgency: low|normal|critical."""
+    if not available():
+        return False
+    try:
+        subprocess.run(
+            ["notify-send", "-a", APP_NAME, "-u", urgency, "-i", _ICON, title, message],
+            timeout=10,
+            check=False,
+        )
+        return True
+    except (subprocess.SubprocessError, OSError):
+        return False
+
+
+class AlertMonitor:
+    """Evaluate samples and raise edge-triggered desktop alerts."""
+
+    def __init__(self, gpu_temp: float = 90.0, cpu_temp: float = 95.0, cooldown: float = 300.0):
+        self.gpu_temp = gpu_temp
+        self.cpu_temp = cpu_temp
+        self.cooldown = cooldown
+        self.enabled = True
+        self._active: dict[str, bool] = {}
+        self._last: dict[str, float] = {}
+
+    def _fire(self, key: str, title: str, message: str, urgency: str = "critical") -> None:
+        if self._active.get(key):
+            return  # already alerting; wait until it clears
+        now = time.time()
+        if now - self._last.get(key, 0.0) < self.cooldown:
+            return
+        self._active[key] = True
+        self._last[key] = now
+        notify(title, message, urgency)
+
+    def _clear(self, key: str) -> None:
+        self._active[key] = False
+
+    def check(self, sample: Sample) -> None:
+        if not self.enabled:
+            return
+        gpu_t = next(
+            (r.value for r in sample.readings
+             if r.source == "gpu" and r.metric == "temp" and r.label == "" and r.value is not None),
+            None,
+        )
+        if gpu_t is not None:
+            if gpu_t >= self.gpu_temp:
+                self._fire("gpu_temp", "GPU overheating", f"GPU at {gpu_t:.0f} °C")
+            else:
+                self._clear("gpu_temp")
+
+        cpu_temps = [r.value for r in sample.readings
+                     if r.source == "cpu" and r.metric == "temp" and r.value is not None]
+        if cpu_temps:
+            cpu_t = max(cpu_temps)
+            if cpu_t >= self.cpu_temp:
+                self._fire("cpu_temp", "CPU overheating", f"CPU at {cpu_t:.0f} °C")
+            else:
+                self._clear("cpu_temp")
+
+        lost = any(r.source == "gpu" and r.metric == "status" and r.label == "query-timeout"
+                   for r in sample.readings)
+        if lost:
+            self._fire("gpu_lost", "GPU not responding", "nvidia-smi query timed out — the GPU may have dropped")
+        else:
+            self._clear("gpu_lost")

src/rigdoctor/core/elevation.py

@@ -0,0 +1,51 @@
+"""Session privilege elevation.
+
+At GUI launch the app asks for the password once (pkexec) and collects the data that
+needs root — SMART health + dmidecode (board/BIOS/RAM) — caching it for the session so
+Health and Inventory can always show the full picture without per-action prompts.
+"""
+
+from __future__ import annotations
+
+import json
+import os
+import shutil
+import subprocess
+import sys
+
+_privileged: dict | None = None
+
+
+def privileged() -> dict | None:
+    """Cached root-collected data ({"smart": [...], "dmidecode": {...}}), or None."""
+    return _privileged
+
+
+def set_privileged(data: dict | None) -> None:
+    global _privileged
+    _privileged = data
+
+
+def available() -> bool:
+    return shutil.which("pkexec") is not None and os.geteuid() != 0
+
+
+def _cli() -> list[str]:
+    candidate = os.path.join(os.path.dirname(sys.executable), "rigdoctor")
+    return [candidate] if os.path.exists(candidate) else [sys.executable, "-m", "rigdoctor"]
+
+
+def collect_via_pkexec(timeout: float = 120.0) -> dict | None:
+    """Run one elevated collection (single password prompt). None if unavailable/cancelled."""
+    if not available():
+        return None
+    try:
+        proc = subprocess.run(
+            ["pkexec", *_cli(), "collect-priv"],
+            capture_output=True, text=True, timeout=timeout,
+        )
+        if proc.returncode == 0 and proc.stdout.strip():
+            return json.loads(proc.stdout)
+    except (subprocess.SubprocessError, OSError, ValueError):
+        pass
+    return None

src/rigdoctor/core/health.py

@@ -234,12 +234,22 @@ def check_live_temps() -> list[Finding]:
 
 
 def run_health_checks() -> list[Finding]:
-    """Run all checks and return findings sorted by severity (worst first)."""
+    """Run all checks and return findings sorted by severity (worst first).
+
+    SMART needs root; if the session collected it via launch elevation, use that
+    instead of re-running smartctl (which would just report "needs root").
+    """
+    from . import elevation
+
     findings: list[Finding] = []
     findings += check_nvidia_driver()
     findings += check_journal()
     findings += check_journal_persistence()
-    findings += check_smart()
+    priv = elevation.privileged()
+    if priv is not None and priv.get("smart") is not None:
+        findings += [Finding(**d) for d in priv["smart"]]
+    else:
+        findings += check_smart()
     findings += check_live_temps()
     findings.sort(key=lambda f: _ORDER.get(f.severity, 9))
     return findings

src/rigdoctor/core/inventory.py

@@ -0,0 +1,206 @@
+"""System inventory (M5): collect hardware/OS details, exportable to Markdown/JSON.
+
+Stdlib + tools already used elsewhere (nvidia-smi, lspci, lsblk, dmidecode). Every
+probe degrades gracefully; board/BIOS/RAM-module details need dmidecode as root.
+"""
+
+from __future__ import annotations
+
+import json
+import os
+import platform
+import shutil
+import subprocess
+from dataclasses import dataclass
+from pathlib import Path
+
+from .. import __version__
+from . import sysenv
+
+
+@dataclass
+class Section:
+    title: str
+    items: list[tuple[str, str]]
+
+
+def _run(cmd: list[str], timeout: float = 12.0) -> str:
+    try:
+        proc = subprocess.run(cmd, capture_output=True, text=True, timeout=timeout)
+        if proc.returncode == 0:
+            return proc.stdout
+    except (subprocess.SubprocessError, OSError):
+        pass
+    return ""
+
+
+def _system() -> Section:
+    u = os.uname()
+    return Section("System", [
+        ("Distro", sysenv.distro_name()),
+        ("Kernel", u.release),
+        ("Architecture", u.machine),
+        ("Hostname", u.nodename),
+        ("Python", platform.python_version()),
+        ("RigDoctor", __version__),
+    ])
+
+
+def _cpu() -> Section:
+    model = "?"
+    threads = 0
+    core_ids: set[tuple[str, str]] = set()
+    phys = "0"
+    try:
+        for line in Path("/proc/cpuinfo").read_text().splitlines():
+            if line.startswith("model name") and model == "?":
+                model = line.split(":", 1)[1].strip()
+            elif line.startswith("processor"):
+                threads += 1
+            elif line.startswith("physical id"):
+                phys = line.split(":", 1)[1].strip()
+            elif line.startswith("core id"):
+                core_ids.add((phys, line.split(":", 1)[1].strip()))
+    except OSError:
+        pass
+    items = [("Model", model)]
+    if core_ids:
+        items.append(("Cores", str(len(core_ids))))
+    items.append(("Threads", str(threads or os.cpu_count() or "?")))
+    return Section("CPU", items)
+
+
+def _firmware(dmi: dict) -> Section:
+    board = dmi.get("baseboard", {})
+    bios = dmi.get("bios", {})
+    items: list[tuple[str, str]] = []
+    if board:
+        items.append(("Motherboard", f"{board.get('Manufacturer', '')} {board.get('Product Name', '')}".strip()))
+    if bios:
+        items.append(("BIOS", f"{bios.get('Vendor', '')} {bios.get('Version', '')}".strip()))
+        if bios.get("Release Date"):
+            items.append(("BIOS date", bios["Release Date"]))
+    if not items:
+        items = [("Motherboard / BIOS", "run with admin (dmidecode needs root)")]
+    return Section("Firmware", items)
+
+
+def _memory(dmi: dict) -> Section:
+    items: list[tuple[str, str]] = []
+    try:
+        for line in Path("/proc/meminfo").read_text().splitlines():
+            if line.startswith("MemTotal"):
+                items.append(("Total", f"{int(line.split()[1]) / 1024 / 1024:.1f} GB"))
+                break
+    except (OSError, ValueError, IndexError):
+        pass
+    modules = dmi.get("memory", [])
+    if modules:
+        items.append(("Modules", str(len(modules))))
+        for i, m in enumerate(modules):
+            desc = " · ".join(p for p in (m.get("Size"), m.get("Type"), m.get("Speed"), m.get("Part Number")) if p)
+            items.append((f"Slot {i}", desc))
+    elif shutil.which("dmidecode"):
+        items.append(("Modules", "run with admin for module details"))
+    return Section("Memory", items)
+
+
+def _gpu() -> Section:
+    if shutil.which("nvidia-smi"):
+        out = _run([
+            "nvidia-smi",
+            "--query-gpu=name,driver_version,vbios_version,memory.total,pcie.link.gen.max,pcie.link.width.max",
+            "--format=csv,noheader",
+        ])
+        line = out.strip().splitlines()[0] if out.strip() else ""
+        if line:
+            cols = [c.strip() for c in line.split(",")]
+            keys = ["Name", "Driver", "VBIOS", "VRAM", "PCIe gen (max)", "PCIe width (max)"]
+            return Section("GPU", list(zip(keys, cols)))
+    out = _run(["lspci"])
+    gpus = [ln.split(":", 2)[-1].strip() for ln in out.splitlines()
+            if "VGA compatible controller" in ln or "3D controller" in ln]
+    return Section("GPU", [("Device", g) for g in gpus] or [("Device", "unknown")])
+
+
+def _storage() -> Section:
+    items: list[tuple[str, str]] = []
+    # TYPE first so MODEL (which can contain spaces) is the trailing field.
+    out = _run(["lsblk", "-dn", "-o", "TYPE,NAME,SIZE,MODEL"])
+    for line in out.strip().splitlines():
+        parts = line.split(None, 3)
+        if len(parts) < 3 or parts[0] != "disk":  # skip loop/zram/rom devices
+            continue
+        name, size = parts[1], parts[2]
+        model = parts[3] if len(parts) > 3 else ""
+        items.append((name, f"{model} ({size})".strip()))
+    return Section("Storage", items or [("Disks", "unknown")])
+
+
+def _display() -> Section:
+    return Section("Display", [
+        ("Session", os.environ.get("XDG_SESSION_TYPE", "unknown")),
+        ("Desktop", os.environ.get("XDG_CURRENT_DESKTOP") or os.environ.get("DESKTOP_SESSION", "unknown")),
+    ])
+
+
+def _dmidecode() -> dict:
+    if not shutil.which("dmidecode"):
+        return {}
+    out = _run(["dmidecode", "-t", "baseboard", "-t", "bios", "-t", "memory"], timeout=15)
+    if not out.strip():
+        return {}
+    result: dict = {"baseboard": {}, "bios": {}, "memory": []}
+    for block in out.split("Handle "):
+        lines = block.splitlines()
+        if len(lines) < 2:
+            continue
+        title = lines[1].strip()
+        kv: dict[str, str] = {}
+        for ln in lines[2:]:
+            if ln.startswith("\t") and ":" in ln:
+                key, _, value = ln.strip().partition(":")
+                kv[key.strip()] = value.strip()
+        if title == "Base Board Information":
+            result["baseboard"] = kv
+        elif title == "BIOS Information":
+            result["bios"] = kv
+        elif title == "Memory Device" and kv.get("Size") and kv["Size"] != "No Module Installed":
+            result["memory"].append(kv)
+    return result
+
+
+def collect() -> list[Section]:
+    from . import elevation
+
+    priv = elevation.privileged()
+    dmi = priv["dmidecode"] if (priv and priv.get("dmidecode") is not None) else _dmidecode()
+    return [_system(), _cpu(), _firmware(dmi), _memory(dmi), _gpu(), _storage(), _display()]
+
+
+def to_dict(sections: list[Section]) -> dict:
+    return {s.title: dict(s.items) for s in sections}
+
+
+def from_dict(data: dict) -> list[Section]:
+    return [Section(title, list(items.items())) for title, items in data.items()]
+
+
+def render_markdown(sections: list[Section]) -> str:
+    out = ["# RigDoctor system inventory", ""]
+    for s in sections:
+        out.append(f"## {s.title}")
+        out += [f"- **{k}:** {v}" for k, v in s.items]
+        out.append("")
+    return "\n".join(out).strip() + "\n"
+
+
+def render_text(sections: list[Section]) -> str:
+    blocks = []
+    for s in sections:
+        blocks.append("\n".join([s.title] + [f"  {k:<18} {v}" for k, v in s.items]))
+    return "\n\n".join(blocks)
+
+
+def render_json(sections: list[Section]) -> str:
+    return json.dumps(to_dict(sections), indent=2, ensure_ascii=False)

src/rigdoctor/core/pty_session.py

@@ -0,0 +1,59 @@
+"""A pseudo-terminal running the host's shell (M12, Tier 3 — host side).
+
+Spawns the user's login shell in a real PTY so interactive programs work over a shared
+session: vim, top, tab-completion, colours, Ctrl-C, and `sudo` (which prompts inside the
+PTY — the host types that password locally, so it's never sent to the guest). Runs as the
+host's own user — never elevated. Linux-only (uses `pty`/`termios`).
+"""
+
+from __future__ import annotations
+
+import fcntl
+import os
+import pty
+import signal
+import struct
+import termios
+
+
+class PtySession:
+    def __init__(self, rows: int = 24, cols: int = 80):
+        self.pid, self.master_fd = pty.fork()
+        if self.pid == 0:  # child: become the shell
+            os.environ["TERM"] = "xterm-256color"
+            shell = os.environ.get("SHELL", "/bin/bash")
+            try:
+                os.execvp(shell, [shell])
+            finally:
+                os._exit(1)
+        os.set_blocking(self.master_fd, False)
+        self.set_size(rows, cols)
+
+    def set_size(self, rows: int, cols: int) -> None:
+        try:
+            fcntl.ioctl(self.master_fd, termios.TIOCSWINSZ, struct.pack("HHHH", rows, cols, 0, 0))
+        except OSError:
+            pass
+
+    def write(self, data: bytes) -> None:
+        try:
+            os.write(self.master_fd, data)
+        except OSError:
+            pass
+
+    def read(self, size: int = 65536) -> bytes:
+        try:
+            return os.read(self.master_fd, size)
+        except (BlockingIOError, OSError):
+            return b""
+
+    def close(self) -> None:
+        try:
+            os.close(self.master_fd)
+        except OSError:
+            pass
+        try:
+            os.kill(self.pid, signal.SIGHUP)
+            os.waitpid(self.pid, os.WNOHANG)
+        except (OSError, ChildProcessError, ProcessLookupError):
+            pass

src/rigdoctor/core/share.py

@@ -0,0 +1,194 @@
+"""Session sharing (M12, Tier 2): a read-only live view over a local HTTP server.
+
+Serves the live sensor snapshot + health report + inventory, **read-only**, gated by a
+random share token. Bind to localhost for local testing, or to all interfaces behind a
+user-chosen tunnel (Tailscale / cloudflared / SSH) for remote help. No actions, no terminal.
+"""
+
+from __future__ import annotations
+
+import json
+import secrets
+from dataclasses import asdict
+from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer
+from urllib.parse import parse_qs, urlparse
+
+from .sampler import Sampler
+from .sources import available_sources
+
+_PAGE = """<!doctype html>
+<html><head><meta charset="utf-8"><title>RigDoctor — shared</title>
+<style>
+ body{background:#101216;color:#e6e8eb;font-family:system-ui,sans-serif;margin:0;padding:24px}
+ h1{font-size:20px;margin:0 0 4px} h2{font-size:14px;color:#8b929c;margin:18px 0 6px}
+ .card{background:#1b1f26;border:1px solid #2a2f39;border-radius:12px;padding:16px;margin:14px 0}
+ table{width:100%;border-collapse:collapse} td{padding:3px 0;font-size:14px}
+ td.v{text-align:right;font-weight:600} .muted{color:#8b929c}
+ .critical{color:#f87171} .warning{color:#fb923c} .ok{color:#4ade80} .info{color:#8b929c}
+ .badge{display:inline-block;background:#38bdf8;color:#06222e;border-radius:6px;padding:1px 8px;font-size:12px;font-weight:700}
+</style></head><body>
+ <h1>RigDoctor <span class="badge">read-only share</span></h1>
+ <p class="muted">A live view shared by the machine's owner. You can look, not change anything.</p>
+ <div class="card"><div id="live">loading…</div></div>
+ <div class="card"><h2 style="margin-top:0">Health</h2><div id="health">loading…</div></div>
+ <div class="card"><h2 style="margin-top:0">Inventory</h2><div id="inv">loading…</div></div>
+<script>
+ const T=new URLSearchParams(location.search).get('t');
+ const j=async p=>(await fetch(p+'?t='+encodeURIComponent(T))).json();
+ const fmt=(v,u)=>v==null?'N/A':(u==='\\u00b0C'?(+v).toFixed(1)+' °C':(u?v+' '+u:v));
+ async function live(){try{const d=await j('/api/snapshot');let h='';
+  for(const[g,items]of Object.entries(d.groups)){h+='<h2>'+g.toUpperCase()+'</h2><table>';
+   for(const it of items)h+='<tr><td class="muted">'+it.name+'</td><td class="v">'+fmt(it.value,it.unit)+'</td></tr>';
+   h+='</table>';}document.getElementById('live').innerHTML=h;}catch(e){}}
+ async function once(){try{const r=await j('/api/report');
+   document.getElementById('health').innerHTML=r.map(f=>'<div><span class="'+f.severity+'">['+f.severity.toUpperCase()+']</span> '+f.category+': '+f.title+'</div>').join('')||'no findings';}catch(e){}
+  try{const inv=await j('/api/inventory');let h='';
+   for(const[s,kv]of Object.entries(inv)){h+='<h2>'+s+'</h2><table>';
+    for(const[k,v]of Object.entries(kv))h+='<tr><td class="muted">'+k+'</td><td class="v">'+v+'</td></tr>';
+    h+='</table>';}document.getElementById('inv').innerHTML=h;}catch(e){}}
+ live();once();setInterval(live,2000);
+</script></body></html>"""
+
+
+def _snapshot(sampler: Sampler) -> dict:
+    sample = sampler.sample()
+    groups: dict[str, list] = {}
+    for r in sample.readings:
+        if r.metric == "name":
+            item = {"name": "device", "value": r.label, "unit": ""}
+        else:
+            item = {"name": (r.label + " " + r.metric).strip() if r.label else r.metric,
+                    "value": r.value, "unit": r.unit}
+        groups.setdefault(r.source, []).append(item)
+    return {"ts": sample.ts, "groups": groups}
+
+
+def _report() -> list:
+    from .health import run_health_checks
+    return [asdict(f) for f in run_health_checks()]
+
+
+def _inventory() -> dict:
+    from .inventory import collect, to_dict
+    return to_dict(collect())
+
+
+# --- Relay (M12) frames: a host streams these; a guest renders them. -----------------
+
+def host_full_frame(sampler: Sampler) -> str:
+    """Initial frame: live snapshot + health report + inventory."""
+    return json.dumps({"type": "full", "snapshot": _snapshot(sampler),
+                       "report": _report(), "inventory": _inventory()})
+
+
+def host_snapshot_frame(sampler: Sampler) -> str:
+    """Recurring frame: just the live snapshot."""
+    return json.dumps({"type": "snapshot", "snapshot": _snapshot(sampler)})
+
+
+def _fmt(value, unit: str) -> str:
+    if value is None:
+        return "N/A"
+    if unit == "°C":
+        try:
+            return f"{float(value):.1f} °C"
+        except (TypeError, ValueError):
+            return str(value)
+    return f"{value} {unit}".strip()
+
+
+def guest_html(snapshot: dict | None, report: list | None, inventory: dict | None) -> str:
+    """Render a received frame as read-only dark HTML for the guest's view."""
+    import html as _html
+
+    def esc(x) -> str:
+        return _html.escape(str(x))
+
+    out = ['<div style="font-family:sans-serif;color:#e6e8eb">']
+    if snapshot:
+        for group, items in snapshot.get("groups", {}).items():
+            out.append(f'<h3 style="color:#8b929c">{esc(group).upper()}</h3><table width="100%">')
+            for it in items:
+                out.append(f'<tr><td style="color:#8b929c">{esc(it.get("name"))}</td>'
+                           f'<td align="right"><b>{esc(_fmt(it.get("value"), it.get("unit", "")))}</b></td></tr>')
+            out.append("</table>")
+    if report:
+        out.append('<h3 style="color:#8b929c">HEALTH</h3>')
+        colors = {"critical": "#f87171", "warning": "#fb923c", "ok": "#4ade80"}
+        for f in report:
+            sev = f.get("severity", "info")
+            out.append(f'<div><span style="color:{colors.get(sev, "#8b929c")}">[{esc(sev).upper()}]</span> '
+                       f'{esc(f.get("category"))}: {esc(f.get("title"))}</div>')
+    if inventory:
+        out.append('<h3 style="color:#8b929c">INVENTORY</h3>')
+        for section, kv in inventory.items():
+            out.append(f'<h4 style="margin:6px 0;color:#8b929c">{esc(section)}</h4><table width="100%">')
+            for k, v in kv.items():
+                out.append(f'<tr><td style="color:#8b929c">{esc(k)}</td><td align="right"><b>{esc(v)}</b></td></tr>')
+            out.append("</table>")
+    out.append("</div>")
+    return "".join(out)
+
+
+class _Handler(BaseHTTPRequestHandler):
+    def log_message(self, *args):  # quiet
+        pass
+
+    def _authed(self, query: dict) -> bool:
+        return secrets.compare_digest(query.get("t", [""])[0], self.server.token)
+
+    def _send(self, code: int, ctype: str, body: bytes) -> None:
+        self.send_response(code)
+        self.send_header("Content-Type", ctype)
+        self.send_header("Content-Length", str(len(body)))
+        self.end_headers()
+        self.wfile.write(body)
+
+    def do_GET(self) -> None:  # noqa: N802
+        parsed = urlparse(self.path)
+        if not self._authed(parse_qs(parsed.query)):
+            self._send(403, "text/plain", b"Forbidden: missing or invalid share token")
+            return
+        if parsed.path == "/":
+            self._send(200, "text/html; charset=utf-8", _PAGE.encode())
+        elif parsed.path == "/api/snapshot":
+            self._send(200, "application/json", json.dumps(_snapshot(self.server.sampler)).encode())
+        elif parsed.path == "/api/report":
+            self._send(200, "application/json", json.dumps(_report()).encode())
+        elif parsed.path == "/api/inventory":
+            self._send(200, "application/json", json.dumps(_inventory()).encode())
+        else:
+            self._send(404, "text/plain", b"Not found")
+
+
+class _Server(ThreadingHTTPServer):
+    daemon_threads = True
+
+    def __init__(self, addr, token: str):
+        super().__init__(addr, _Handler)
+        self.token = token
+        self.sampler = Sampler(available_sources())
+
+
+def make_server(host: str = "127.0.0.1", port: int = 0, token: str | None = None) -> tuple[_Server, str]:
+    token = token or secrets.token_urlsafe(16)
+    return _Server((host, port), token), token
+
+
+def serve(host: str = "127.0.0.1", port: int = 8765) -> int:
+    srv, token = make_server(host, port)
+    url = f"http://{host}:{srv.server_address[1]}/?t={token}"
+    print(
+        f"Sharing a read-only live view at:\n  {url}\n\n"
+        "Anyone with this URL (and network access to this host) can VIEW your sensors,\n"
+        "health report, and inventory — read-only. For remote help, expose it via a tunnel\n"
+        "(Tailscale / cloudflared / `ssh -R`). Press Ctrl-C to stop sharing.",
+        flush=True,
+    )
+    try:
+        srv.serve_forever()
+    except KeyboardInterrupt:
+        print("\nStopped sharing.")
+    finally:
+        srv.shutdown()
+    return 0

src/rigdoctor/core/steam.py

@@ -0,0 +1,340 @@
+"""Steam library & game detection (M6, the Steam piece of D12 game detection).
+
+Discovers a user's Steam installs, the library folders they've configured (Steam tracks
+them all in ``libraryfolders.vdf``, so multiple libraries on multiple drives are covered),
+and the games installed in each (one ``appmanifest_<appid>.acf`` per app). Stdlib only —
+no Steam tooling required, every probe degrades gracefully.
+
+The set of libraries actually scanned is user-chosen (config ``steam_libraries``); nothing
+is scanned until the user opts a library in. Scan results are cached in ``games.json`` so the
+GUI can show the list instantly and the launch-time background scan can diff against it to
+flag newly-installed games.
+"""
+
+from __future__ import annotations
+
+import json
+import os
+import time
+from dataclasses import asdict, dataclass
+from pathlib import Path
+
+from ..config import GAMES_FILE, load_config
+
+# Steam "apps" that aren't games: runtimes, Proton builds, redistributables. Filtered out of
+# scans by appid (known IDs) or by name prefix (covers future Proton/runtime versions).
+_TOOL_APPIDS = {
+    "228980",   # Steamworks Common Redistributables
+    "1070560",  # Steam Linux Runtime 1.0 (scout)
+    "1391110",  # Steam Linux Runtime 2.0 (soldier)
+    "1628350",  # Steam Linux Runtime 3.0 (sniper)
+    "1493710",  # Proton Experimental
+    "2180100",  # Proton Hotfix
+    "1826330",  # Proton EasyAntiCheat Runtime
+    "1161040",  # Proton BattlEye Runtime
+}
+_TOOL_NAME_PREFIXES = ("Proton", "Steam Linux Runtime", "Steamworks Common")
+
+# Where Steam may be installed (native + Flatpak + Snap). Symlinks (~/.steam/steam) are
+# resolved and de-duplicated by real path.
+_ROOT_CANDIDATES = (
+    "~/.steam/steam",
+    "~/.steam/root",
+    "~/.local/share/Steam",
+    "~/.var/app/com.valvesoftware.Steam/data/Steam",  # Flatpak
+    "~/snap/steam/common/.local/share/Steam",          # Snap
+)
+
+
+@dataclass
+class SteamLibrary:
+    path: str          # the library root (contains a steamapps/ dir)
+    label: str = ""    # Steam's label for the folder, if any
+
+
+@dataclass
+class Game:
+    appid: str
+    name: str
+    library: str       # library path the game lives in
+    installdir: str    # folder name under <library>/steamapps/common
+    size_bytes: int = 0
+    last_updated: int = 0  # epoch seconds (acf LastUpdated), 0 if unknown
+
+
+# --- VDF (Valve Data Format) parsing --------------------------------------------------
+# Minimal text-VDF reader: quoted "key" "value" pairs and "key" { ... } nesting. Enough
+# for libraryfolders.vdf and appmanifest_*.acf; ignores #base/#include and unquoted tokens.
+
+def _parse_vdf(text: str) -> dict:
+    pos = 0
+    n = len(text)
+
+    def skip_ws() -> None:
+        nonlocal pos
+        while pos < n:
+            c = text[pos]
+            if c in " \t\r\n":
+                pos += 1
+            elif c == "/" and pos + 1 < n and text[pos + 1] == "/":  # // line comment
+                while pos < n and text[pos] != "\n":
+                    pos += 1
+            else:
+                break
+
+    def read_string() -> str:
+        nonlocal pos
+        pos += 1  # opening quote
+        out = []
+        while pos < n:
+            c = text[pos]
+            if c == "\\" and pos + 1 < n:
+                nxt = text[pos + 1]
+                out.append({"n": "\n", "t": "\t", "\\": "\\", '"': '"'}.get(nxt, nxt))
+                pos += 2
+                continue
+            if c == '"':
+                pos += 1
+                break
+            out.append(c)
+            pos += 1
+        return "".join(out)
+
+    def parse_obj() -> dict:
+        nonlocal pos
+        obj: dict = {}
+        while True:
+            skip_ws()
+            if pos >= n or text[pos] == "}":
+                pos += 1  # consume closing brace (or run off the end)
+                return obj
+            if text[pos] != '"':  # skip unquoted/unsupported tokens defensively
+                pos += 1
+                continue
+            key = read_string()
+            skip_ws()
+            if pos < n and text[pos] == "{":
+                pos += 1
+                obj[key] = parse_obj()
+            elif pos < n and text[pos] == '"':
+                obj[key] = read_string()
+            else:  # malformed; bail on this key
+                obj[key] = ""
+        return obj
+
+    skip_ws()
+    if pos < n and text[pos] == '"':
+        root_key = read_string()
+        skip_ws()
+        if pos < n and text[pos] == "{":
+            pos += 1
+            return {root_key: parse_obj()}
+    return {}
+
+
+def _read_vdf(path: Path) -> dict:
+    try:
+        return _parse_vdf(path.read_text(encoding="utf-8", errors="replace"))
+    except OSError:
+        return {}
+
+
+# --- discovery ------------------------------------------------------------------------
+
+def steam_roots() -> list[Path]:
+    """Existing Steam install roots, de-duplicated by resolved path."""
+    seen: set[Path] = set()
+    roots: list[Path] = []
+    for cand in _ROOT_CANDIDATES:
+        p = Path(os.path.expanduser(cand))
+        if not p.exists():
+            continue
+        real = p.resolve()
+        if real in seen:
+            continue
+        seen.add(real)
+        roots.append(real)
+    return roots
+
+
+def _libraryfolders_vdf(root: Path) -> Path | None:
+    for rel in ("steamapps/libraryfolders.vdf", "config/libraryfolders.vdf"):
+        p = root / rel
+        if p.exists():
+            return p
+    return None
+
+
+def discover_libraries() -> list[SteamLibrary]:
+    """Every Steam library folder configured on this machine, de-duplicated by real path.
+
+    Reads each install's ``libraryfolders.vdf`` (which lists all drives/folders), and
+    always includes the install root itself as a fallback.
+    """
+    seen: set[Path] = set()
+    libs: list[SteamLibrary] = []
+
+    def add(path: Path, label: str = "") -> None:
+        if not (path / "steamapps").is_dir():
+            return
+        real = path.resolve()
+        if real in seen:
+            return
+        seen.add(real)
+        libs.append(SteamLibrary(path=str(real), label=label))
+
+    for root in steam_roots():
+        vdf = _libraryfolders_vdf(root)
+        folders = _read_vdf(vdf).get("libraryfolders", {}) if vdf else {}
+        if isinstance(folders, dict):
+            for entry in folders.values():
+                if isinstance(entry, dict) and entry.get("path"):
+                    add(Path(entry["path"]), entry.get("label", ""))
+        add(root)  # the install root is itself a library
+    return libs
+
+
+# --- game scanning --------------------------------------------------------------------
+
+def is_tool(appid: str, name: str) -> bool:
+    """True for non-game Steam apps (runtimes, Proton, redistributables)."""
+    if appid in _TOOL_APPIDS:
+        return True
+    return name.startswith(_TOOL_NAME_PREFIXES)
+
+
+def scan_library(library: str) -> list[Game]:
+    """Games installed in one library, parsed from its appmanifest_*.acf files."""
+    steamapps = Path(library) / "steamapps"
+    games: list[Game] = []
+    try:
+        manifests = sorted(steamapps.glob("appmanifest_*.acf"))
+    except OSError:
+        return games
+    for manifest in manifests:
+        state = _read_vdf(manifest).get("AppState", {})
+        if not isinstance(state, dict):
+            continue
+        # Steam treats VDF keys case-insensitively (e.g. "SizeOnDisk" but "lastupdated").
+        state = {k.lower(): v for k, v in state.items()}
+        appid = state.get("appid", "")
+        name = state.get("name", "").strip()
+        if not appid or not name or is_tool(appid, name):
+            continue
+        games.append(Game(
+            appid=appid,
+            name=name,
+            library=str(library),
+            installdir=state.get("installdir", ""),
+            size_bytes=_int(state.get("sizeondisk")),
+            last_updated=_int(state.get("lastupdated")),
+        ))
+    return games
+
+
+def scan_games(libraries: list[str]) -> list[Game]:
+    """All games across the given libraries, de-duplicated by appid, sorted by name."""
+    by_appid: dict[str, Game] = {}
+    for lib in libraries:
+        for game in scan_library(lib):
+            by_appid.setdefault(game.appid, game)  # first library wins on duplicates
+    return sorted(by_appid.values(), key=lambda g: g.name.lower())
+
+
+def _int(value) -> int:
+    try:
+        return int(value)
+    except (TypeError, ValueError):
+        return 0
+
+
+# --- config-driven selection ----------------------------------------------------------
+
+def selected_library_paths(cfg: dict | None = None) -> list[str]:
+    """Library paths the user has opted in to scanning (config ``steam_libraries``)."""
+    cfg = cfg or load_config()
+    paths = cfg.get("steam_libraries") or []
+    return [str(p) for p in paths]
+
+
+# --- scan cache + new-game detection --------------------------------------------------
+
+@dataclass
+class ScanResult:
+    games: list[Game]
+    new_appids: list[str]   # newly-installed since the last scan (badge fuel)
+    scanned_at: float
+
+
+def load_cache() -> dict | None:
+    try:
+        return json.loads(GAMES_FILE.read_text())
+    except (OSError, ValueError):
+        return None
+
+
+def _save_cache(games: list[Game], known: set[str], new: list[str], when: float) -> None:
+    GAMES_FILE.parent.mkdir(parents=True, exist_ok=True)
+    data = {
+        "scanned_at": when,
+        "known_appids": sorted(known),
+        "new_appids": new,
+        "games": [asdict(g) for g in games],
+    }
+    GAMES_FILE.write_text(json.dumps(data, indent=2, ensure_ascii=False))
+
+
+def cached_games() -> list[Game]:
+    """Games from the last scan (for instant display before a rescan finishes)."""
+    cache = load_cache()
+    if not cache:
+        return []
+    return [Game(**{k: g.get(k) for k in Game.__dataclass_fields__}) for g in cache.get("games", [])]
+
+
+def rescan(cfg: dict | None = None) -> ScanResult:
+    """Scan the selected libraries, diff against the cache, and persist the result.
+
+    Newly-installed games (appids never seen before) are reported in ``new_appids``. The
+    very first scan reports nothing as new (so the whole library isn't flagged at once);
+    unacknowledged new games carry forward until they're acknowledged or uninstalled.
+    """
+    games = scan_games(selected_library_paths(cfg))
+    current = {g.appid for g in games}
+    prev = load_cache()
+    if prev is None:
+        known: set[str] = set(current)  # first run: everything is "known", nothing new
+        new = []
+    else:
+        known = set(prev.get("known_appids", []))
+        carried = set(prev.get("new_appids", [])) & current  # still-unacknowledged & installed
+        new = sorted((current - known) | carried)
+        known |= current
+    when = time.time()
+    _save_cache(games, known, new, when)
+    return ScanResult(games=games, new_appids=new, scanned_at=when)
+
+
+def acknowledge_new() -> None:
+    """Clear the new-game badge (called when the user views the games list)."""
+    cache = load_cache()
+    if not cache or not cache.get("new_appids"):
+        return
+    cache["new_appids"] = []
+    try:
+        GAMES_FILE.write_text(json.dumps(cache, indent=2, ensure_ascii=False))
+    except OSError:
+        pass
+
+
+# --- formatting -----------------------------------------------------------------------
+
+def human_size(num_bytes: int) -> str:
+    if num_bytes <= 0:
+        return "—"
+    size = float(num_bytes)
+    for unit in ("B", "KB", "MB", "GB", "TB"):
+        if size < 1024 or unit == "TB":
+            return f"{size:.0f} {unit}" if unit in ("B", "KB") else f"{size:.1f} {unit}"
+        size /= 1024
+    return f"{size:.1f} TB"

src/rigdoctor/core/uninstall.py

@@ -23,6 +23,7 @@ def targets(purge: bool = False) -> list[Path]:
         home / ".local" / "bin" / "rigdoctor",
         home / ".local" / "bin" / "rigdoctor-gui",
         share / "applications" / "rigdoctor.desktop",
+        share / "icons" / "hicolor" / "scalable" / "apps" / "rigdoctor.svg",
     ]
     if purge:
         items += [config.CONFIG_DIR, config.STATE_DIR, config.DATA_DIR]

src/rigdoctor/gui/app.py

@@ -3,18 +3,28 @@
 from __future__ import annotations
 
 import sys
+from pathlib import Path
 
+from PySide6.QtGui import QIcon
 from PySide6.QtWidgets import QApplication
 
 from ..config import load_config
+from . import desktop
 from .main_window import MainWindow
 from .theme import STYLESHEET
 
+ICON = Path(__file__).parent / "assets" / "rigdoctor.svg"
+
 
 def main(argv: list[str] | None = None) -> int:
+    desktop.ensure()  # self-register icon + .desktop so updates show it without re-installing
     app = QApplication(argv if argv is not None else sys.argv)
     app.setApplicationName("RigDoctor")
     app.setApplicationDisplayName("RigDoctor")
+    # Match the installed rigdoctor.desktop so the dock/launcher shows our icon (Wayland app-id).
+    app.setDesktopFileName("rigdoctor")
+    if ICON.exists():
+        app.setWindowIcon(QIcon(str(ICON)))
     app.setStyle("Fusion")
     app.setStyleSheet(STYLESHEET)
 

src/rigdoctor/gui/assets/check.svg

@@ -0,0 +1,4 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 16 16">
+  <path d="M3.5 8.5 L6.5 11.5 L12.5 4.5" fill="none" stroke="#06222e"
+        stroke-width="2.4" stroke-linecap="round" stroke-linejoin="round"/>
+</svg>

src/rigdoctor/gui/assets/rigdoctor.svg

@@ -0,0 +1,8 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="256" height="256" viewBox="0 0 256 256">
+  <rect x="8" y="8" width="240" height="240" rx="52" fill="#15181e"/>
+  <circle cx="128" cy="128" r="84" fill="none" stroke="#2a2f39" stroke-width="14"/>
+  <path d="M128 44 a84 84 0 1 1 -59.4 24.6" fill="none" stroke="#38bdf8"
+        stroke-width="14" stroke-linecap="round"/>
+  <path d="M60 132 H100 L116 96 L140 168 L156 132 H196" fill="none" stroke="#e6e8eb"
+        stroke-width="14" stroke-linecap="round" stroke-linejoin="round"/>
+</svg>

src/rigdoctor/gui/desktop.py

@@ -0,0 +1,51 @@
+"""Best-effort desktop integration: install our icon + .desktop so the dock shows it.
+
+Runs at GUI launch (idempotent), so a self-update + relaunch refreshes the icon without
+re-running install.sh. No-op for non-installed (dev) runs where the launcher is absent.
+"""
+
+from __future__ import annotations
+
+import shutil
+import sys
+from pathlib import Path
+
+from .. import config
+
+_ICON_SRC = Path(__file__).parent / "assets" / "rigdoctor.svg"
+
+_DESKTOP = """[Desktop Entry]
+Type=Application
+Name=RigDoctor
+Comment=Hardware monitoring & crash diagnostics for Linux gamers
+Exec={exec}
+Icon=rigdoctor
+Terminal=false
+Categories=System;Monitor;Utility;
+StartupWMClass=rigdoctor
+"""
+
+
+def ensure() -> None:
+    share = config.DATA_DIR.parent  # ~/.local/share
+
+    try:
+        if _ICON_SRC.exists():
+            icon_dst = share / "icons" / "hicolor" / "scalable" / "apps" / "rigdoctor.svg"
+            icon_dst.parent.mkdir(parents=True, exist_ok=True)
+            if not icon_dst.exists() or icon_dst.read_bytes() != _ICON_SRC.read_bytes():
+                shutil.copyfile(_ICON_SRC, icon_dst)
+    except OSError:
+        pass
+
+    gui_exec = Path(sys.executable).with_name("rigdoctor-gui")
+    if not gui_exec.exists():  # dev / not a normal install — don't fabricate a .desktop
+        return
+    try:
+        desktop = share / "applications" / "rigdoctor.desktop"
+        content = _DESKTOP.format(exec=gui_exec)
+        desktop.parent.mkdir(parents=True, exist_ok=True)
+        if not desktop.exists() or desktop.read_text() != content:
+            desktop.write_text(content)
+    except OSError:
+        pass

src/rigdoctor/gui/games_page.py

@@ -0,0 +1,249 @@
+"""Games page (M6 in the GUI): pick Steam libraries and browse detected games.
+
+Libraries are opt-in — the user checks which ones to scan. The list is loaded from the
+cache instantly, then a background rescan refreshes it and flags games installed since the
+last scan (a "NEW" badge here + a count on the sidebar nav).
+"""
+
+from __future__ import annotations
+
+import os
+import threading
+import time
+
+from PySide6.QtCore import Qt, QTimer, Signal
+from PySide6.QtWidgets import (
+    QCheckBox,
+    QFrame,
+    QHBoxLayout,
+    QLabel,
+    QPushButton,
+    QScrollArea,
+    QVBoxLayout,
+    QWidget,
+)
+
+from ..config import load_config, update_config
+from .theme import ACCENT, GOOD, MUTED
+
+
+def _game_row(name: str, sublabel: str, size: str, is_new: bool) -> QFrame:
+    card = QFrame()
+    card.setObjectName("Card")
+    h = QHBoxLayout(card)
+    h.setContentsMargins(16, 10, 16, 10)
+    h.setSpacing(10)
+
+    left = QVBoxLayout()
+    left.setSpacing(2)
+    title = QLabel(name)
+    title.setStyleSheet("font-weight: 600; background: transparent;")
+    title.setWordWrap(True)
+    left.addWidget(title)
+    if sublabel:
+        sub = QLabel(sublabel)
+        sub.setObjectName("Muted")
+        left.addWidget(sub)
+    h.addLayout(left, 1)
+
+    if is_new:
+        badge = QLabel("NEW")
+        badge.setStyleSheet(
+            f"color: {GOOD}; border: 1px solid {GOOD}; border-radius: 6px; "
+            f"padding: 1px 6px; font-weight: 700; background: transparent;"
+        )
+        h.addWidget(badge, 0, Qt.AlignmentFlag.AlignVCenter)
+
+    size_label = QLabel(size)
+    size_label.setObjectName("Muted")
+    size_label.setMinimumWidth(80)
+    size_label.setAlignment(Qt.AlignmentFlag.AlignRight | Qt.AlignmentFlag.AlignVCenter)
+    h.addWidget(size_label, 0)
+    return card
+
+
+class GamesPage(QWidget):
+    _libraries_ready = Signal(object)  # list[dict(path, label, count, selected)]
+    _scanned = Signal(object)          # steam.ScanResult
+    new_count_changed = Signal(int)    # newly-installed game count (for the nav badge)
+
+    def __init__(self) -> None:
+        super().__init__()
+        self.setObjectName("Page")
+        self._libraries_ready.connect(self._render_libraries)
+        self._scanned.connect(self._render_games)
+        self._busy = False
+        self._new_appids: set[str] = set()
+
+        root = QVBoxLayout(self)
+        root.setContentsMargins(20, 18, 20, 18)
+        root.setSpacing(16)
+
+        header = QHBoxLayout()
+        title = QLabel("Games")
+        title.setObjectName("PageTitle")
+        header.addWidget(title)
+        header.addStretch(1)
+        self._status = QLabel("")
+        self._status.setObjectName("Muted")
+        header.addWidget(self._status)
+        self._rescan_btn = QPushButton("Rescan")
+        self._rescan_btn.setObjectName("PrimaryButton")
+        self._rescan_btn.clicked.connect(self.refresh)
+        header.addWidget(self._rescan_btn)
+        root.addLayout(header)
+
+        # Libraries (opt-in checkboxes)
+        lib_card = QFrame()
+        lib_card.setObjectName("Card")
+        lib_v = QVBoxLayout(lib_card)
+        lib_v.setContentsMargins(16, 12, 16, 12)
+        lib_v.setSpacing(6)
+        lib_head = QLabel("Steam libraries")
+        lib_head.setStyleSheet("font-weight: 700; background: transparent;")
+        lib_v.addWidget(lib_head)
+        self._lib_box = QVBoxLayout()
+        self._lib_box.setSpacing(6)
+        lib_v.addLayout(self._lib_box)
+        self._lib_hint = QLabel("Looking for Steam libraries…")
+        self._lib_hint.setObjectName("Muted")
+        self._lib_hint.setWordWrap(True)
+        lib_v.addWidget(self._lib_hint)
+        root.addWidget(lib_card)
+
+        # Games list
+        scroll = QScrollArea()
+        scroll.setWidgetResizable(True)
+        scroll.setFrameShape(QFrame.Shape.NoFrame)
+        scroll.setStyleSheet("background: transparent;")
+        self._container = QWidget()
+        self._list = QVBoxLayout(self._container)
+        self._list.setContentsMargins(0, 0, 0, 0)
+        self._list.setSpacing(8)
+        self._list.setAlignment(Qt.AlignmentFlag.AlignTop)
+        scroll.setWidget(self._container)
+        root.addWidget(scroll, 1)
+
+        self._load_cached()                       # instant display from the last scan
+        QTimer.singleShot(400, self.refresh)      # then rescan in the background on launch
+
+    # --- loading ----------------------------------------------------------------------
+
+    def _load_cached(self) -> None:
+        from ..core import steam
+
+        cache = steam.load_cache() or {}
+        self._new_appids = set(cache.get("new_appids", []))
+        games = steam.cached_games()
+        if games:
+            self._populate_games(games, self._new_appids)
+        self.new_count_changed.emit(len(self._new_appids))
+
+    def refresh(self) -> None:
+        if self._busy:
+            return
+        self._busy = True
+        self._rescan_btn.setEnabled(False)
+        self._status.setText("Scanning Steam libraries…")
+        threading.Thread(target=self._work, daemon=True).start()
+
+    def _work(self) -> None:
+        from ..core import steam
+
+        try:
+            selected = {os.path.realpath(p) for p in steam.selected_library_paths()}
+            libs = [
+                {"path": lib.path, "label": lib.label, "selected": lib.path in selected,
+                 "count": len(steam.scan_library(lib.path))}
+                for lib in steam.discover_libraries()
+            ]
+            self._libraries_ready.emit(libs)
+            self._scanned.emit(steam.rescan())
+        except Exception:
+            self._scanned.emit(None)
+
+    # --- rendering --------------------------------------------------------------------
+
+    def _render_libraries(self, libs) -> None:
+        while self._lib_box.count():
+            item = self._lib_box.takeAt(0)
+            w = item.widget()
+            if w is not None:
+                w.deleteLater()
+        if not libs:
+            self._lib_hint.setText("No Steam libraries detected. Is Steam installed?")
+            self._lib_hint.show()
+            return
+        self._lib_hint.hide()
+        for lib in libs:
+            label = lib["path"]
+            if lib["label"]:
+                label += f"  [{lib['label']}]"
+            cb = QCheckBox(f"{label}    ·  {lib['count']} games")
+            cb.setChecked(lib["selected"])
+            cb.toggled.connect(lambda checked, p=lib["path"]: self._toggle_library(p, checked))
+            self._lib_box.addWidget(cb)
+
+    def _toggle_library(self, path: str, checked: bool) -> None:
+        selected = {os.path.realpath(p) for p in (load_config().get("steam_libraries") or [])}
+        if checked:
+            selected.add(os.path.realpath(path))
+        else:
+            selected.discard(os.path.realpath(path))
+        update_config(steam_libraries=sorted(selected))
+        self.refresh()
+
+    def _render_games(self, result) -> None:
+        self._busy = False
+        self._rescan_btn.setEnabled(True)
+        if result is None:
+            self._status.setText("scan failed")
+            return
+        self._new_appids = set(result.new_appids)
+        self._populate_games(result.games, self._new_appids)
+        new = len(self._new_appids)
+        suffix = f"  ·  {new} new" if new else ""
+        self._status.setText(
+            f"{len(result.games)} games  ·  {time.strftime('%H:%M:%S')}{suffix}"
+        )
+        self.new_count_changed.emit(new)
+
+    def _populate_games(self, games, new_appids: set[str]) -> None:
+        from ..core import steam
+
+        while self._list.count():
+            item = self._list.takeAt(0)
+            w = item.widget()
+            if w is not None:
+                w.deleteLater()
+
+        if not games:
+            empty = QLabel(
+                "No games to show yet — check a Steam library above to scan it for games."
+            )
+            empty.setObjectName("Muted")
+            empty.setWordWrap(True)
+            self._list.addWidget(empty)
+            self._list.addStretch(1)
+            return
+
+        for g in games:
+            self._list.addWidget(_game_row(
+                g.name,
+                os.path.basename(g.library.rstrip("/")) or g.library,
+                steam.human_size(g.size_bytes),
+                g.appid in new_appids,
+            ))
+        self._list.addStretch(1)
+
+    # --- nav badge integration --------------------------------------------------------
+
+    def showEvent(self, event) -> None:  # noqa: N802 (Qt override)
+        # Viewing the list acknowledges the new games: clear the sidebar badge. The NEW
+        # tags stay on the rows for this session so the user can still spot them.
+        super().showEvent(event)
+        if self._new_appids:
+            from ..core import steam
+
+            threading.Thread(target=steam.acknowledge_new, daemon=True).start()
+            self.new_count_changed.emit(0)

src/rigdoctor/gui/health_page.py

@@ -2,11 +2,6 @@
 
 from __future__ import annotations
 
-import json
-import os
-import shutil
-import subprocess
-import sys
 import threading
 import time
 
@@ -77,11 +72,6 @@ class HealthPage(QWidget):
         self._status = QLabel("")
         self._status.setObjectName("Muted")
         header.addWidget(self._status)
-        self._admin_btn = QPushButton("Run with admin")
-        self._admin_btn.setToolTip("Run all checks with root (SMART needs it) — prompts for your password")
-        self._admin_btn.clicked.connect(self._run_admin)
-        self._admin_btn.setEnabled(shutil.which("pkexec") is not None)
-        header.addWidget(self._admin_btn)
         self._run_btn = QPushButton("Run health report")
         self._run_btn.setObjectName("PrimaryButton")
         self._run_btn.clicked.connect(self._run)
@@ -116,32 +106,10 @@ class HealthPage(QWidget):
             findings = []
         self._result.emit(findings)
 
-    def _run_admin(self) -> None:
-        self._run_btn.setEnabled(False)
-        self._admin_btn.setEnabled(False)
-        self._status.setText("Running all checks with admin (you'll be prompted)…")
-        threading.Thread(target=self._work_admin, daemon=True).start()
-
-    def _work_admin(self) -> None:
-        from ..core.health import Finding
-
-        cli = os.path.join(os.path.dirname(sys.executable), "rigdoctor")
-        if os.path.exists(cli):
-            cmd = ["pkexec", cli, "report", "--json"]
-        else:  # dev / not on PATH next to python
-            cmd = ["pkexec", sys.executable, "-m", "rigdoctor", "report", "--json"]
-        try:
-            proc = subprocess.run(cmd, capture_output=True, text=True, timeout=180)
-            findings = [Finding(**d) for d in json.loads(proc.stdout)] if proc.returncode == 0 else None
-        except Exception:
-            findings = None  # pkexec cancelled / failed / unparsable
-        self._result.emit(findings)
-
     def _render_findings(self, findings) -> None:
         self._run_btn.setEnabled(True)
-        self._admin_btn.setEnabled(shutil.which("pkexec") is not None)
+        if findings is None:  # collection failed — keep current results
-        if findings is None:  # elevated run cancelled/failed — keep current results
+            self._status.setText("check failed")
-            self._status.setText("admin run cancelled")
             return
 
         while self._list.count():

src/rigdoctor/gui/main_window.py

@@ -7,6 +7,7 @@ import sys
 import threading
 
 from PySide6.QtCore import Qt, QProcess, QTimer, Signal
+from PySide6.QtGui import QTextDocument
 from PySide6.QtWidgets import (
     QApplication,
     QButtonGroup,
@@ -25,29 +26,31 @@ from PySide6.QtWidgets import (
 
 from .. import __version__
 from ..config import load_config
-from ..core import updates
+from ..core import alerts, elevation, updates
 from .dashboard import Dashboard
+from .games_page import GamesPage
 from .health_page import HealthPage
+from .notifications_page import NotificationsPage
 from .recorder_page import RecorderPage
 from .setup_page import SetupPage
+from .share_page import SharePage
 from .theme import ACCENT, GOOD, MUTED
 from .worker import SamplerWorker
 
-_NAV_ITEMS = ["Dashboard", "Logs", "Health", "Setup", "Inventory"]
+_NAV_ITEMS = ["Dashboard", "Logs", "Health", "Games", "Setup", "Notifications", "Share"]
-_PLACEHOLDERS = {
-    "Inventory": "System inventory (M5) — CPU/GPU/board/RAM/drivers — lands here.",
-}
 
 
 class MainWindow(QMainWindow):
     _update_checked = Signal(object)  # (state, tag, notes)
     _update_applied = Signal(int)     # pip exit code
     _changelog_ready = Signal(object)  # ([(tag, date, notes)], error)
+    _elevated = Signal()              # privileged data collected at launch
 
     def __init__(self, interval: float = 1.0) -> None:
         super().__init__()
         self.setWindowTitle("RigDoctor")
         self.resize(1000, 680)
+        cfg = load_config()
 
         central = QWidget()
         self.setCentralWidget(central)
@@ -64,12 +67,19 @@ class MainWindow(QMainWindow):
         self.dashboard = Dashboard()
         self.recorder_page = RecorderPage()
         self.health_page = HealthPage()
+        self.games_page = GamesPage()
+        self.games_page.new_count_changed.connect(self._set_games_badge)
         self.setup_page = SetupPage()
+        self.notifications_page = NotificationsPage()
+        self.notifications_page.changed.connect(self._apply_alert_settings)
+        self.share_page = SharePage()
         self._stack.addWidget(self.dashboard)            # 0 Dashboard
         self._stack.addWidget(self.recorder_page)        # 1 Logs
         self._stack.addWidget(self.health_page)          # 2 Health
-        self._stack.addWidget(self.setup_page)           # 3 Setup
+        self._stack.addWidget(self.games_page)           # 3 Games
-        self._stack.addWidget(self._placeholder_page("Inventory", _PLACEHOLDERS["Inventory"]))  # 4
+        self._stack.addWidget(self.setup_page)           # 4 Setup
+        self._stack.addWidget(self.notifications_page)   # 5 Notifications
+        self._stack.addWidget(self.share_page)           # 6 Share
         content_layout.addWidget(self._stack)
 
         layout.addWidget(self._build_sidebar())
@@ -77,8 +87,24 @@ class MainWindow(QMainWindow):
 
         self._worker = SamplerWorker(interval=interval)
         self._worker.sampled.connect(self.dashboard.update_sample)
+        # Desktop alerts (M8): overheat / GPU-lost from the sample stream, new-version below.
+        # Configurable on the Notifications page; gated by AlertMonitor.enabled.
+        self._notified_update_tag = None
+        self._alert_monitor = alerts.AlertMonitor(
+            gpu_temp=float(cfg.get("gpu_temp_alert", 90.0)),
+            cpu_temp=float(cfg.get("cpu_temp_alert", 95.0)),
+        )
+        self._alert_monitor.enabled = bool(cfg.get("alerts_enabled", True))
+        self._worker.sampled.connect(self._alert_monitor.check)
         self._worker.start()
 
+        # Ask for the password once at launch and collect root-only data (SMART +
+        # dmidecode); Health/Inventory then always show the full picture (config:
+        # elevate_on_launch). Falls back silently to non-root if cancelled/unavailable.
+        if cfg.get("elevate_on_launch", True) and elevation.available():
+            self._elevated.connect(self._on_elevated)
+            threading.Thread(target=self._collect_privileged, daemon=True).start()
+
         # Update check (M13): once at launch, then periodically so a newly published
         # release is detected without restarting (interval from config; 0 disables).
         self._latest_tag = None
@@ -88,7 +114,7 @@ class MainWindow(QMainWindow):
         self._update_applied.connect(self._on_update_applied)
         self._changelog_ready.connect(self._on_changelog)
         self._start_update_check()
-        minutes = float(load_config().get("update_check_minutes", 30) or 0)
+        minutes = float(cfg.get("update_check_minutes", 30) or 0)
         if minutes > 0:
             self._update_timer = QTimer(self)
             self._update_timer.setInterval(int(minutes * 60_000))
@@ -113,6 +139,7 @@ class MainWindow(QMainWindow):
 
         group = QButtonGroup(self)
         group.setExclusive(True)
+        self._nav_buttons: dict[str, QPushButton] = {}
         for i, name in enumerate(_NAV_ITEMS):
             btn = QPushButton(name)
             btn.setObjectName("NavButton")
@@ -122,6 +149,7 @@ class MainWindow(QMainWindow):
             btn.clicked.connect(lambda _checked, idx=i: self._stack.setCurrentIndex(idx))
             group.addButton(btn, i)
             v.addWidget(btn)
+            self._nav_buttons[name] = btn
 
         v.addStretch(1)
         live = QLabel(f'<span style="color:{ACCENT};">●</span> <span style="color:{MUTED};">Live</span>')
@@ -172,7 +200,9 @@ class MainWindow(QMainWindow):
         box = QMessageBox(self)
         box.setWindowTitle(f"Update to {self._latest_tag}")
         box.setText(f"Update RigDoctor to {self._latest_tag}?")
-        box.setInformativeText(self._latest_notes or "(no release notes)")
+        notes_doc = QTextDocument()
+        notes_doc.setMarkdown(self._latest_notes or "_(no release notes)_")
+        box.setInformativeText(notes_doc.toHtml())  # render Markdown as rich text (#1)
         box.setStandardButtons(QMessageBox.StandardButton.Ok | QMessageBox.StandardButton.Cancel)
         box.button(QMessageBox.StandardButton.Ok).setText("Update")
         if box.exec() != QMessageBox.StandardButton.Ok:
@@ -194,6 +224,28 @@ class MainWindow(QMainWindow):
             self._update_label.setText("update failed")
             self._update_btn.setEnabled(True)
 
+    def _collect_privileged(self) -> None:
+        data = elevation.collect_via_pkexec()
+        if data is not None:
+            elevation.set_privileged(data)
+            self._elevated.emit()
+
+    def _on_elevated(self) -> None:
+        # Re-run Health now that root-only SMART data is available. (dmidecode is still
+        # collected and used by the relay guest view + the CLI `rigdoctor inventory`.)
+        self.health_page._run()
+
+    def _set_games_badge(self, count: int) -> None:
+        btn = self._nav_buttons.get("Games")
+        if btn is not None:
+            btn.setText(f"Games   ● {count}" if count > 0 else "Games")
+
+    def _apply_alert_settings(self) -> None:
+        cfg = load_config()
+        self._alert_monitor.enabled = bool(cfg.get("alerts_enabled", True))
+        self._alert_monitor.gpu_temp = float(cfg.get("gpu_temp_alert", 90.0))
+        self._alert_monitor.cpu_temp = float(cfg.get("cpu_temp_alert", 95.0))
+
     def _manual_check(self) -> None:
         if self._applied:
             return
@@ -233,9 +285,9 @@ class MainWindow(QMainWindow):
             return
         blocks = []
         for tag, date, notes in releases:
-            head = tag + (f"   ({date})" if date else "")
+            title = f"## {tag}" + (f" — {date}" if date else "")
-            blocks.append(f"{head}\n{'─' * len(head)}\n{notes or '(no notes)'}")
+            blocks.append(f"{title}\n\n{notes or '_(no notes)_'}")
-        view.setPlainText("\n\n".join(blocks))
+        view.setMarkdown("\n\n".join(blocks))  # render Markdown instead of raw text (#1)
 
     def _check_updates(self) -> None:
         self._update_checked.emit(updates.update_state())
@@ -257,32 +309,13 @@ class MainWindow(QMainWindow):
             self._update_label.setText(f'<span style="color:{GOOD};">{tag} available</span>')
             self._update_btn.setText(f"Update to {tag}")
             self._update_btn.setVisible(True)
+            if self._alert_monitor.enabled and tag != self._notified_update_tag:
+                self._notified_update_tag = tag  # once per version, not every poll
+                alerts.notify("Update available", f"RigDoctor {tag} is available — open RigDoctor to update.")
         else:  # UP_TO_DATE
             self._update_label.setText("up-to-date")
 
-    def _placeholder_page(self, title: str, description: str) -> QWidget:
-        page = QWidget()
-        page.setObjectName("Page")
-        v = QVBoxLayout(page)
-        v.setContentsMargins(20, 18, 20, 18)
-        v.setSpacing(16)
-        head = QLabel(title)
-        head.setObjectName("PageTitle")
-        v.addWidget(head)
-
-        card = QFrame()
-        card.setObjectName("Card")
-        cv = QVBoxLayout(card)
-        cv.setContentsMargins(24, 48, 24, 48)
-        msg = QLabel(description)
-        msg.setObjectName("Muted")
-        msg.setWordWrap(True)
-        msg.setAlignment(Qt.AlignmentFlag.AlignCenter)
-        cv.addWidget(msg)
-        v.addWidget(card)
-        v.addStretch(1)
-        return page
-
     def closeEvent(self, event) -> None:  # noqa: N802 (Qt override)
         self._worker.stop()
+        self.share_page.shutdown()
         super().closeEvent(event)

src/rigdoctor/gui/notifications_page.py

@@ -0,0 +1,108 @@
+"""Notifications page (M8 config): user-configurable alert settings."""
+
+from __future__ import annotations
+
+from PySide6.QtCore import Qt, Signal
+from PySide6.QtWidgets import (
+    QCheckBox,
+    QDoubleSpinBox,
+    QFrame,
+    QGridLayout,
+    QHBoxLayout,
+    QLabel,
+    QPushButton,
+    QVBoxLayout,
+    QWidget,
+)
+
+from ..config import load_config, update_config
+from ..core import alerts
+
+
+class NotificationsPage(QWidget):
+    changed = Signal()  # settings saved — main window re-applies them live
+
+    def __init__(self) -> None:
+        super().__init__()
+        self.setObjectName("Page")
+        root = QVBoxLayout(self)
+        root.setContentsMargins(20, 18, 20, 18)
+        root.setSpacing(16)
+
+        title = QLabel("Notifications")
+        title.setObjectName("PageTitle")
+        root.addWidget(title)
+
+        card = QFrame()
+        card.setObjectName("Card")
+        v = QVBoxLayout(card)
+        v.setContentsMargins(16, 14, 16, 14)
+        v.setSpacing(10)
+        head = QLabel("Alerts")
+        head.setStyleSheet("font-weight: 700; background: transparent;")
+        v.addWidget(head)
+
+        self._enabled = QCheckBox("Enable desktop notifications")
+        v.addWidget(self._enabled)
+
+        grid = QGridLayout()
+        grid.setHorizontalSpacing(12)
+        grid.setColumnStretch(2, 1)
+        self._gpu = self._spin()
+        self._cpu = self._spin()
+        grid.addWidget(QLabel("GPU temperature alert"), 0, 0)
+        grid.addWidget(self._gpu, 0, 1)
+        grid.addWidget(QLabel("CPU temperature alert"), 1, 0)
+        grid.addWidget(self._cpu, 1, 1)
+        v.addLayout(grid)
+
+        note = QLabel("GPU-lost and new-version alerts are included whenever notifications are enabled.")
+        note.setObjectName("Muted")
+        note.setWordWrap(True)
+        v.addWidget(note)
+
+        buttons = QHBoxLayout()
+        save = QPushButton("Save")
+        save.setObjectName("PrimaryButton")
+        save.clicked.connect(self._save)
+        test = QPushButton("Send test")
+        test.clicked.connect(self._test)
+        buttons.addWidget(save)
+        buttons.addWidget(test)
+        buttons.addStretch(1)
+        v.addLayout(buttons)
+        self._status = QLabel("")
+        self._status.setObjectName("Muted")
+        v.addWidget(self._status)
+
+        root.addWidget(card)
+        root.addStretch(1)
+        self._load()
+
+    @staticmethod
+    def _spin() -> QDoubleSpinBox:
+        spin = QDoubleSpinBox()
+        spin.setRange(40, 110)
+        spin.setDecimals(0)
+        spin.setSingleStep(1)
+        spin.setSuffix(" °C")
+        return spin
+
+    def _load(self) -> None:
+        cfg = load_config()
+        self._enabled.setChecked(bool(cfg.get("alerts_enabled", True)))
+        self._gpu.setValue(float(cfg.get("gpu_temp_alert", 90.0)))
+        self._cpu.setValue(float(cfg.get("cpu_temp_alert", 95.0)))
+
+    def _save(self) -> None:
+        update_config(
+            alerts_enabled=self._enabled.isChecked(),
+            gpu_temp_alert=self._gpu.value(),
+            cpu_temp_alert=self._cpu.value(),
+        )
+        self.changed.emit()
+        self._status.setText("Saved.")
+
+    def _test(self) -> None:
+        ok = alerts.notify("RigDoctor", "Test notification — alerts are working.")
+        self._status.setText("Test notification sent." if ok else "notify-send not found — install libnotify-bin (Setup).")

src/rigdoctor/gui/setup_page.py

@@ -86,8 +86,13 @@ class SetupPage(QWidget):
         comp_layout.addLayout(controls)
         root.addWidget(comp_card)
 
-        # Update access (M13): token gating updates to Gitea account holders.
+        # Account access (M13/M12): one Gitea token gates updates and session sharing.
-        upd_card, upd_layout = _panel("Update access")
+        upd_card, upd_layout = _panel("Account access")
+        hint = QLabel("A Gitea access token unlocks updates and session sharing. "
+                      "Create it with scopes <b>read:user</b> and <b>read:repository</b>.")
+        hint.setObjectName("Muted")
+        hint.setWordWrap(True)
+        upd_layout.addWidget(hint)
         self._upd_status = QLabel("")
         self._upd_status.setObjectName("Muted")
         self._upd_status.setWordWrap(True)
@@ -95,7 +100,7 @@ class SetupPage(QWidget):
         token_row = QHBoxLayout()
         self._token_input = QLineEdit()
         self._token_input.setEchoMode(QLineEdit.EchoMode.Password)
-        self._token_input.setPlaceholderText("Paste a Gitea token (scope: read:repository)")
+        self._token_input.setPlaceholderText("Paste a Gitea token (read:user + read:repository)")
         save_btn = QPushButton("Save token")
         save_btn.setObjectName("PrimaryButton")
         save_btn.clicked.connect(self._save_token)

src/rigdoctor/gui/share_page.py

@@ -0,0 +1,348 @@
+"""Share page (M12): host or join a shared session over the relay.
+
+Guest sees the host's live sensors + health + inventory (read-only). If the host enables it,
+a full **PTY terminal** is shared: the guest types and the commands run on the host (as the
+host's user), the host reads along, and the host can type too — e.g. a sudo password, which
+stays local and is never sent to the guest.
+"""
+
+from __future__ import annotations
+
+import base64
+import json
+
+from PySide6.QtCore import Qt, QSocketNotifier, QTimer, QUrl
+from PySide6.QtWebSockets import QWebSocket
+from PySide6.QtWidgets import (
+    QCheckBox,
+    QFrame,
+    QHBoxLayout,
+    QLabel,
+    QLineEdit,
+    QPushButton,
+    QTextEdit,
+    QVBoxLayout,
+    QWidget,
+)
+
+from ..config import load_config, load_token
+from ..core import share
+from ..core.pty_session import PtySession
+from ..core.sampler import Sampler
+from ..core.sources import available_sources
+from .terminal_widget import TerminalView
+
+
+def _relay_url() -> str:
+    return load_config().get("relay_url", "wss://rigdoctor.jesseyvanofferen.com").rstrip("/")
+
+
+def _b64(data: bytes) -> str:
+    return base64.b64encode(data).decode("ascii")
+
+
+def _card(title: str) -> tuple[QFrame, QVBoxLayout]:
+    card = QFrame()
+    card.setObjectName("Card")
+    v = QVBoxLayout(card)
+    v.setContentsMargins(16, 14, 16, 14)
+    v.setSpacing(10)
+    head = QLabel(title)
+    head.setStyleSheet("font-weight: 700; background: transparent;")
+    v.addWidget(head)
+    return card, v
+
+
+class SharePage(QWidget):
+    def __init__(self) -> None:
+        super().__init__()
+        self.setObjectName("Page")
+        self._sampler = Sampler(available_sources())
+        self._host_ws: QWebSocket | None = None
+        self._guest_ws: QWebSocket | None = None
+        self._pty: PtySession | None = None
+        self._pty_notifier: QSocketNotifier | None = None
+        self._last_report = None
+        self._last_inv = None
+        self._timer = QTimer(self)
+        self._timer.setInterval(2000)
+        self._timer.timeout.connect(self._stream)
+
+        root = QVBoxLayout(self)
+        root.setContentsMargins(20, 18, 20, 18)
+        root.setSpacing(14)
+        title = QLabel("Share")
+        title.setObjectName("PageTitle")
+        root.addWidget(title)
+        root.addWidget(self._build_host())
+        root.addWidget(self._build_guest(), 1)
+
+    # ------------------------------------------------------------------ host
+    def _build_host(self) -> QFrame:
+        card, v = _card("Start a shared session")
+        self._host_status = QLabel("Let someone with an account view your machine, read-only.")
+        self._host_status.setObjectName("Muted")
+        self._host_status.setWordWrap(True)
+        v.addWidget(self._host_status)
+
+        row = QHBoxLayout()
+        self._start_btn = QPushButton("Start shared session")
+        self._start_btn.setObjectName("PrimaryButton")
+        self._start_btn.clicked.connect(self._start_host)
+        self._stop_btn = QPushButton("Stop")
+        self._stop_btn.setEnabled(False)
+        self._stop_btn.clicked.connect(self._stop_host)
+        self._code_label = QLabel("")
+        self._code_label.setStyleSheet("font-weight:700; font-size:18px; color:#38bdf8; background:transparent;")
+        self._code_label.setTextInteractionFlags(Qt.TextInteractionFlag.TextSelectableByMouse)
+        row.addWidget(self._start_btn)
+        row.addWidget(self._stop_btn)
+        row.addSpacing(12)
+        row.addWidget(self._code_label)
+        row.addStretch(1)
+        v.addLayout(row)
+
+        self._allow_term = QCheckBox("Allow remote terminal — the guest runs commands as your user (you read along; you can type too, e.g. a sudo password)")
+        self._allow_term.setStyleSheet("color:#fb923c; background:transparent;")
+        self._allow_term.toggled.connect(self._toggle_terminal)
+        v.addWidget(self._allow_term)
+
+        self._host_term = TerminalView()
+        self._host_term.keys.connect(lambda b: self._pty.write(b) if self._pty else None)
+        self._host_term.resized.connect(lambda r, c: self._pty.set_size(r, c) if self._pty else None)
+        self._host_term.setVisible(False)
+        v.addWidget(self._host_term)
+        return card
+
+    def _start_host(self) -> None:
+        if not load_token():
+            self._host_status.setText("Set a Gitea access token in Setup → Account access first.")
+            return
+        self._host_status.setText("Connecting to the relay…")
+        self._start_btn.setEnabled(False)
+        self._host_ws = QWebSocket()
+        self._host_ws.connected.connect(lambda: self._host_ws.sendTextMessage(json.dumps({"token": load_token()})))
+        self._host_ws.textMessageReceived.connect(self._host_msg)
+        self._host_ws.disconnected.connect(self._host_closed)
+        self._host_ws.errorOccurred.connect(lambda *_: self._host_status.setText(f"Relay error: {self._host_ws.errorString()}"))
+        self._host_ws.open(QUrl(_relay_url() + "/ws/host"))
+
+    def _host_msg(self, text: str) -> None:
+        try:
+            data = json.loads(text)
+        except ValueError:
+            return
+        if data.get("error"):
+            self._host_status.setText(f"Rejected: {data['error']}")
+            return
+        if "code" in data:  # relay handshake
+            self._code_label.setText(data["code"])
+            self._host_status.setText(f"Sharing as {data.get('user', '?')} — give this code to whoever should view your machine.")
+            self._stop_btn.setEnabled(True)
+            self._host_ws.sendTextMessage(share.host_full_frame(self._sampler))
+            self._send_terminal_state()
+            if self._allow_term.isChecked():
+                self._start_pty()
+            self._timer.start()
+            return
+        kind = data.get("type")  # frames forwarded from a guest
+        if kind == "req_full":
+            # A guest just joined — send a full frame AND the current terminal state, so a
+            # guest that joins *after* the host enabled the terminal still gets access.
+            self._host_ws.sendTextMessage(share.host_full_frame(self._sampler))
+            self._send_terminal_state()
+        elif kind == "pty_in" and self._pty:
+            self._pty.write(base64.b64decode(data["data"]))
+        elif kind == "pty_resize" and self._pty:
+            self._pty.set_size(int(data["rows"]), int(data["cols"]))
+
+    def _toggle_terminal(self, on: bool) -> None:
+        if on and self._host_ws and self._code_label.text():
+            self._start_pty()
+        elif not on:
+            self._stop_pty()
+        self._send_terminal_state()
+
+    def _send_terminal_state(self) -> None:
+        if self._host_ws and self._code_label.text():
+            self._host_ws.sendTextMessage(json.dumps({"type": "terminal", "enabled": self._allow_term.isChecked()}))
+
+    def _start_pty(self) -> None:
+        if self._pty:
+            return
+        rows, cols = self._host_term.grid()
+        self._pty = PtySession(rows=rows, cols=cols)
+        self._pty_notifier = QSocketNotifier(self._pty.master_fd, QSocketNotifier.Type.Read, self)
+        self._pty_notifier.activated.connect(self._on_pty_output)
+        self._host_term.reset()
+        self._host_term.setVisible(True)
+
+    def _on_pty_output(self) -> None:
+        if not self._pty:
+            return
+        data = self._pty.read()
+        if not data:  # shell exited / EOF
+            self._stop_pty()
+            self._send_terminal_state()
+            self._allow_term.setChecked(False)
+            return
+        self._host_term.feed(data)
+        if self._host_ws:
+            self._host_ws.sendTextMessage(json.dumps({"type": "pty", "data": _b64(data)}))
+
+    def _stop_pty(self) -> None:
+        if self._pty_notifier:
+            self._pty_notifier.setEnabled(False)
+            self._pty_notifier = None
+        if self._pty:
+            self._pty.close()
+            self._pty = None
+        self._host_term.setVisible(False)
+
+    def _stream(self) -> None:
+        if self._host_ws:
+            self._host_ws.sendTextMessage(share.host_snapshot_frame(self._sampler))
+
+    def _stop_host(self) -> None:
+        self._timer.stop()
+        self._stop_pty()
+        if self._host_ws:
+            self._host_ws.close()
+            self._host_ws = None
+        self._code_label.setText("")
+        self._stop_btn.setEnabled(False)
+        self._start_btn.setEnabled(True)
+        self._host_status.setText("Stopped sharing.")
+
+    def _host_closed(self) -> None:
+        self._timer.stop()
+        self._stop_pty()
+        self._start_btn.setEnabled(True)
+        self._stop_btn.setEnabled(False)
+        if self._code_label.text():
+            self._code_label.setText("")
+            self._host_status.setText("Disconnected from the relay.")
+
+    # ----------------------------------------------------------------- guest
+    def _build_guest(self) -> QFrame:
+        card, v = _card("Join a shared session")
+        row = QHBoxLayout()
+        self._code_input = QLineEdit()
+        self._code_input.setPlaceholderText("Enter share code")
+        self._code_input.setMaxLength(6)
+        self._code_input.setFixedWidth(160)
+        self._join_btn = QPushButton("Join")
+        self._join_btn.setObjectName("PrimaryButton")
+        self._join_btn.clicked.connect(self._join)
+        self._leave_btn = QPushButton("Leave")
+        self._leave_btn.setEnabled(False)
+        self._leave_btn.clicked.connect(self._leave)
+        row.addWidget(self._code_input)
+        row.addWidget(self._join_btn)
+        row.addWidget(self._leave_btn)
+        row.addStretch(1)
+        v.addLayout(row)
+        self._guest_status = QLabel("")
+        self._guest_status.setObjectName("Muted")
+        v.addWidget(self._guest_status)
+
+        self._view = QTextEdit()
+        self._view.setObjectName("Report")
+        self._view.setReadOnly(True)
+        self._view.setVisible(False)
+        self._view.setMinimumHeight(200)
+        v.addWidget(self._view)
+
+        self._term_label = QLabel("")
+        self._term_label.setObjectName("Muted")
+        self._term_label.setVisible(False)
+        v.addWidget(self._term_label)
+        self._guest_term = TerminalView()
+        self._guest_term.keys.connect(self._guest_key)
+        self._guest_term.resized.connect(self._guest_resize)
+        self._guest_term.setVisible(False)
+        v.addWidget(self._guest_term)
+        return card
+
+    def _join(self) -> None:
+        code = self._code_input.text().strip().upper()
+        if not load_token():
+            self._guest_status.setText("Set a Gitea access token in Setup → Account access first.")
+            return
+        if not code:
+            self._guest_status.setText("Enter a share code.")
+            return
+        self._guest_status.setText("Connecting…")
+        self._join_btn.setEnabled(False)
+        self._guest_ws = QWebSocket()
+        self._guest_ws.connected.connect(lambda: self._guest_ws.sendTextMessage(json.dumps({"token": load_token()})))
+        self._guest_ws.textMessageReceived.connect(self._guest_msg)
+        self._guest_ws.disconnected.connect(self._guest_closed)
+        self._guest_ws.errorOccurred.connect(lambda *_: self._guest_status.setText(f"Relay error: {self._guest_ws.errorString()}"))
+        self._guest_ws.open(QUrl(_relay_url() + "/ws/guest/" + code))
+
+    def _guest_msg(self, text: str) -> None:
+        try:
+            data = json.loads(text)
+        except ValueError:
+            return
+        if data.get("error"):
+            self._guest_status.setText(data["error"])
+            return
+        if "joined" in data:
+            self._guest_status.setText(f"Viewing {data.get('host', '?')}'s machine — read-only.")
+            self._leave_btn.setEnabled(True)
+            self._view.setVisible(True)
+            self._guest_ws.sendTextMessage(json.dumps({"type": "req_full"}))
+            return
+        kind = data.get("type")
+        if kind in ("full", "snapshot"):
+            if kind == "full":
+                self._last_report = data.get("report")
+                self._last_inv = data.get("inventory")
+            self._view.setHtml(share.guest_html(data.get("snapshot"), self._last_report, self._last_inv))
+        elif kind == "terminal":
+            self._set_terminal_visible(bool(data.get("enabled")))
+        elif kind == "pty":
+            self._guest_term.feed(base64.b64decode(data["data"]))
+
+    def _set_terminal_visible(self, enabled: bool) -> None:
+        self._term_label.setVisible(True)
+        self._term_label.setText("Terminal enabled by host — your keystrokes run on their machine. Click here and type."
+                                 if enabled else "Terminal not enabled by the host.")
+        self._guest_term.setVisible(enabled)
+        if enabled:
+            self._guest_term.reset()
+            self._guest_resize(*self._guest_term.grid())
+            self._guest_term.setFocus()
+
+    def _guest_key(self, data: bytes) -> None:
+        if self._guest_ws:
+            self._guest_ws.sendTextMessage(json.dumps({"type": "pty_in", "data": _b64(data)}))
+
+    def _guest_resize(self, rows: int, cols: int) -> None:
+        if self._guest_ws:
+            self._guest_ws.sendTextMessage(json.dumps({"type": "pty_resize", "rows": rows, "cols": cols}))
+
+    def _leave(self) -> None:
+        if self._guest_ws:
+            self._guest_ws.close()
+            self._guest_ws = None
+        for w in (self._view, self._term_label, self._guest_term):
+            w.setVisible(False)
+        self._leave_btn.setEnabled(False)
+        self._join_btn.setEnabled(True)
+        self._guest_status.setText("Left the session.")
+
+    def _guest_closed(self) -> None:
+        self._join_btn.setEnabled(True)
+        self._leave_btn.setEnabled(False)
+        if self._view.isVisible():
+            self._guest_status.setText("Session ended (host disconnected).")
+
+    def shutdown(self) -> None:
+        self._timer.stop()
+        self._stop_pty()
+        for ws in (self._host_ws, self._guest_ws):
+            if ws:
+                ws.close()

src/rigdoctor/gui/terminal_widget.py

@@ -0,0 +1,98 @@
+"""A minimal terminal view: renders PTY output via pyte and emits keystrokes (M12, Tier 3).
+
+Used by both sides of a shared session — the host (mirrors its local PTY, can also type, e.g.
+a sudo password) and the guest (renders the streamed PTY, sends keystrokes). Monochrome for
+now; cursor addressing / layout (vim, top) work via pyte.
+"""
+
+from __future__ import annotations
+
+import pyte
+from PySide6.QtCore import Qt, Signal
+from PySide6.QtGui import QFontDatabase, QFontMetrics, QTextCursor
+from PySide6.QtWidgets import QPlainTextEdit
+
+
+class TerminalView(QPlainTextEdit):
+    keys = Signal(bytes)        # user keystrokes -> bytes for the PTY
+    resized = Signal(int, int)  # rows, cols
+
+    def __init__(self, rows: int = 24, cols: int = 80):
+        super().__init__()
+        self.setLineWrapMode(QPlainTextEdit.LineWrapMode.NoWrap)
+        self.setFont(QFontDatabase.systemFont(QFontDatabase.SystemFont.FixedFont))
+        self.setUndoRedoEnabled(False)
+        self.setMinimumHeight(260)
+        self._rows, self._cols = rows, cols
+        self._screen = pyte.HistoryScreen(cols, rows, history=1000, ratio=0.5)
+        self._stream = pyte.ByteStream(self._screen)
+
+    def grid(self) -> tuple[int, int]:
+        return self._rows, self._cols
+
+    def feed(self, data: bytes) -> None:
+        self._stream.feed(data)
+        self._render()
+
+    def reset(self) -> None:
+        self._screen.reset()
+        self._render()
+
+    def _row_text(self, row) -> str:
+        return "".join(row[x].data for x in range(self._cols)).rstrip()
+
+    def _render(self) -> None:
+        bar = self.verticalScrollBar()
+        at_bottom = bar.value() >= bar.maximum() - 2
+        prev = bar.value()
+        history = [self._row_text(r) for r in self._screen.history.top]  # scrollback
+        self.setPlainText("\n".join(history + list(self._screen.display)))
+        if at_bottom:  # follow output; place caret at the real (row, col)
+            cursor = self.textCursor()
+            cursor.movePosition(QTextCursor.MoveOperation.Start)
+            cursor.movePosition(QTextCursor.MoveOperation.Down, QTextCursor.MoveMode.MoveAnchor, len(history) + self._screen.cursor.y)
+            cursor.movePosition(QTextCursor.MoveOperation.Right, QTextCursor.MoveMode.MoveAnchor, self._screen.cursor.x)
+            self.setTextCursor(cursor)
+            self.ensureCursorVisible()
+        else:  # user scrolled up to read — keep their place
+            bar.setValue(prev)
+
+    def resizeEvent(self, event):  # noqa: N802 (Qt override)
+        super().resizeEvent(event)
+        fm = QFontMetrics(self.font())
+        cw = max(1, fm.horizontalAdvance("M"))
+        ch = max(1, fm.height())
+        cols = max(20, self.viewport().width() // cw)
+        rows = max(6, self.viewport().height() // ch)
+        if (rows, cols) != (self._rows, self._cols):
+            self._rows, self._cols = rows, cols
+            self._screen.resize(rows, cols)
+            self._render()
+            self.resized.emit(rows, cols)
+
+    def keyPressEvent(self, event):  # noqa: N802 (Qt override)
+        data = self._translate(event)
+        if data:
+            self.keys.emit(data)
+        event.accept()  # display comes from PTY output, not local editing
+
+    @staticmethod
+    def _translate(event) -> bytes:
+        key = event.key()
+        mod = event.modifiers()
+        k = Qt.Key
+        if mod & Qt.KeyboardModifier.ControlModifier and k.Key_A.value <= key <= k.Key_Z.value:
+            return bytes([key - k.Key_A.value + 1])  # Ctrl-A..Ctrl-Z
+        special = {
+            k.Key_Return.value: b"\r", k.Key_Enter.value: b"\r",
+            k.Key_Backspace.value: b"\x7f", k.Key_Tab.value: b"\t",
+            k.Key_Escape.value: b"\x1b",
+            k.Key_Up.value: b"\x1b[A", k.Key_Down.value: b"\x1b[B",
+            k.Key_Right.value: b"\x1b[C", k.Key_Left.value: b"\x1b[D",
+            k.Key_Home.value: b"\x1b[H", k.Key_End.value: b"\x1b[F",
+            k.Key_Delete.value: b"\x1b[3~", k.Key_PageUp.value: b"\x1b[5~", k.Key_PageDown.value: b"\x1b[6~",
+        }
+        if key in special:
+            return special[key]
+        text = event.text()
+        return text.encode("utf-8") if text else b""

src/rigdoctor/gui/theme.py

@@ -2,6 +2,10 @@
 
 from __future__ import annotations
 
+from pathlib import Path
+
+_CHECK = (Path(__file__).parent / "assets" / "check.svg").as_posix()
+
 # Palette (dark)
 BG = "#101216"
 SIDEBAR = "#15181e"
@@ -10,6 +14,7 @@ CARD_BORDER = "#2a2f39"
 TRACK = "#2a2f39"
 TEXT = "#e6e8eb"
 MUTED = "#8b929c"
+INPUT_BG = "#0d0f13"  # form-control background (must stay dark — see contrast rule)
 
 ACCENT = "#38bdf8"
 COLD = "#7dd3fc"  # icey-blue
@@ -120,8 +125,29 @@ QPushButton#LinkButton {{
 }}
 QPushButton#LinkButton:hover {{ color: {TEXT}; }}
 
+QCheckBox {{ spacing: 8px; background: transparent; }}
+QCheckBox::indicator {{
+    width: 17px; height: 17px; border-radius: 4px;
+    border: 1px solid {MUTED}; background: #262b34;
+}}
+QCheckBox::indicator:hover {{ border-color: {ACCENT}; }}
+QCheckBox::indicator:checked {{
+    background: {ACCENT}; border-color: {ACCENT}; image: url("{_CHECK}");
+}}
+
 /* Dialogs (update prompt, changelog) — match the dark theme so text is readable. */
 QDialog {{ background: {BG}; }}
 QMessageBox {{ background: {CARD}; }}
 QDialog QLabel, QMessageBox QLabel {{ color: {TEXT}; background: transparent; }}
+
+/* Form controls: keep dark bg + light text (Fusion defaults to light-on-light here). */
+QLineEdit, QPlainTextEdit, QAbstractSpinBox, QComboBox {{
+    background: {INPUT_BG}; color: {TEXT};
+    border: 1px solid {CARD_BORDER}; border-radius: 6px; padding: 5px 8px;
+    selection-background-color: {ACCENT}; selection-color: #06222e;
+}}
+QLineEdit:focus, QPlainTextEdit:focus, QAbstractSpinBox:focus, QComboBox:focus {{
+    border: 1px solid {ACCENT};
+}}
+QLineEdit:disabled, QPlainTextEdit:disabled, QAbstractSpinBox:disabled {{ color: {MUTED}; }}
 """

tests/test_alerts.py

@@ -0,0 +1,38 @@
+"""Tests for the M8 alert monitor (edge-triggered; notify mocked)."""
+
+import unittest
+from unittest import mock
+
+from rigdoctor.core import alerts
+from rigdoctor.core.sample import Reading, Sample
+
+
+def _gpu(temp):
+    return Sample(readings=[Reading("gpu", "temp", temp, "°C")])
+
+
+class AlertTests(unittest.TestCase):
+    @mock.patch.object(alerts, "notify")
+    def test_edge_triggered_no_repeat(self, m):
+        mon = alerts.AlertMonitor(gpu_temp=90.0, cooldown=0.0)
+        mon.check(_gpu(95))   # fires
+        mon.check(_gpu(96))   # still hot — no repeat while active
+        self.assertEqual(m.call_count, 1)
+        mon.check(_gpu(50))   # clears
+        mon.check(_gpu(95))   # hot again — fires
+        self.assertEqual(m.call_count, 2)
+
+    @mock.patch.object(alerts, "notify")
+    def test_no_alert_below_threshold(self, m):
+        alerts.AlertMonitor(gpu_temp=90.0).check(_gpu(70))
+        m.assert_not_called()
+
+    @mock.patch.object(alerts, "notify")
+    def test_gpu_lost(self, m):
+        mon = alerts.AlertMonitor()
+        mon.check(Sample(readings=[Reading("gpu", "status", None, "", "query-timeout")]))
+        m.assert_called_once()
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/test_config.py

@@ -0,0 +1,42 @@
+"""Tests for config save/load (flat TOML writer)."""
+
+import tempfile
+import unittest
+from pathlib import Path
+from unittest import mock
+
+from rigdoctor import config
+
+
+class ConfigTests(unittest.TestCase):
+    def test_save_load_round_trip(self):
+        with tempfile.TemporaryDirectory() as d:
+            cf = Path(d) / "config.toml"
+            with mock.patch.object(config, "CONFIG_FILE", cf), mock.patch.object(config, "CONFIG_DIR", Path(d)):
+                config.save_config({"alerts_enabled": False, "gpu_temp_alert": 88.0, "update_check_minutes": 5})
+                loaded = config.load_config()
+                self.assertIs(loaded["alerts_enabled"], False)
+                self.assertEqual(loaded["gpu_temp_alert"], 88.0)
+                self.assertEqual(loaded["update_check_minutes"], 5)
+
+    def test_list_value_round_trip(self):
+        with tempfile.TemporaryDirectory() as d:
+            cf = Path(d) / "config.toml"
+            with mock.patch.object(config, "CONFIG_FILE", cf), mock.patch.object(config, "CONFIG_DIR", Path(d)):
+                paths = ["/home/u/.local/share/Steam", "/mnt/games/SteamLibrary"]
+                config.update_config(steam_libraries=paths)
+                self.assertEqual(config.load_config()["steam_libraries"], paths)
+                config.update_config(steam_libraries=[])
+                self.assertEqual(config.load_config()["steam_libraries"], [])
+
+    def test_update_config_merges_and_keeps_defaults(self):
+        with tempfile.TemporaryDirectory() as d:
+            cf = Path(d) / "config.toml"
+            with mock.patch.object(config, "CONFIG_FILE", cf), mock.patch.object(config, "CONFIG_DIR", Path(d)):
+                config.update_config(cpu_temp_alert=70.0)
+                self.assertEqual(config.load_config()["cpu_temp_alert"], 70.0)
+                self.assertEqual(config.load_config()["gpu_temp_alert"], 90.0)  # default preserved
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/test_inventory.py

@@ -0,0 +1,30 @@
+"""Tests for the M5 system inventory (render + dict round-trip; collect on real system)."""
+
+import unittest
+
+from rigdoctor.core import inventory
+from rigdoctor.core.inventory import Section
+
+
+class InventoryTests(unittest.TestCase):
+    def test_collect_returns_sections(self):
+        sections = inventory.collect()
+        self.assertTrue(sections)
+        titles = {s.title for s in sections}
+        self.assertIn("System", titles)
+        self.assertIn("CPU", titles)
+
+    def test_dict_round_trip(self):
+        sections = [Section("System", [("Kernel", "7.0.0"), ("Distro", "Ubuntu")])]
+        restored = inventory.from_dict(inventory.to_dict(sections))
+        self.assertEqual(restored[0].title, "System")
+        self.assertEqual(restored[0].items, [("Kernel", "7.0.0"), ("Distro", "Ubuntu")])
+
+    def test_render_markdown(self):
+        md = inventory.render_markdown([Section("CPU", [("Model", "Test CPU")])])
+        self.assertIn("## CPU", md)
+        self.assertIn("- **Model:** Test CPU", md)
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/test_pty_session.py

@@ -0,0 +1,27 @@
+"""Tests for the host PTY session (M12 Tier 3)."""
+
+import time
+import unittest
+
+from rigdoctor.core.pty_session import PtySession
+
+
+class PtySessionTests(unittest.TestCase):
+    def test_runs_command_and_reads_output(self):
+        pty = PtySession(rows=24, cols=80)
+        try:
+            time.sleep(0.4)
+            pty.read()  # drain the shell prompt
+            pty.write(b"echo PTY_MARKER_42\n")
+            deadline = time.time() + 3
+            buf = ""
+            while time.time() < deadline and "PTY_MARKER_42" not in buf:
+                time.sleep(0.1)
+                buf += pty.read().decode(errors="replace")
+            self.assertIn("PTY_MARKER_42", buf)
+        finally:
+            pty.close()
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/test_relay_frames.py

@@ -0,0 +1,38 @@
+"""Tests for M12 relay frames + guest HTML rendering (host/guest data shapes)."""
+
+import json
+import unittest
+
+from rigdoctor.core import share
+from rigdoctor.core.sampler import Sampler
+from rigdoctor.core.sources import available_sources
+
+
+class RelayFrameTests(unittest.TestCase):
+    def setUp(self):
+        self.sampler = Sampler(available_sources())
+
+    def test_full_frame_shape(self):
+        frame = json.loads(share.host_full_frame(self.sampler))
+        self.assertEqual(frame["type"], "full")
+        self.assertIn("groups", frame["snapshot"])
+        self.assertIsInstance(frame["report"], list)
+        self.assertIsInstance(frame["inventory"], dict)
+
+    def test_snapshot_frame_shape(self):
+        frame = json.loads(share.host_snapshot_frame(self.sampler))
+        self.assertEqual(frame["type"], "snapshot")
+        self.assertIn("groups", frame["snapshot"])
+
+    def test_guest_html_renders(self):
+        snap = {"groups": {"gpu": [{"name": "temp", "value": 51.0, "unit": "°C"}]}}
+        report = [{"severity": "ok", "category": "Logs", "title": "No errors"}]
+        inv = {"System": {"Kernel": "7.0.0"}}
+        html = share.guest_html(snap, report, inv)
+        self.assertIn("51.0 °C", html)
+        self.assertIn("No errors", html)
+        self.assertIn("Kernel", html)
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/test_share.py

@@ -0,0 +1,46 @@
+"""Tests for M12 Tier 2 share server: token gating + endpoints."""
+
+import json
+import threading
+import unittest
+import urllib.error
+import urllib.request
+
+from rigdoctor.core import share
+
+
+class ShareServerTests(unittest.TestCase):
+    def setUp(self):
+        self.srv, self.token = share.make_server("127.0.0.1", 0)
+        self.port = self.srv.server_address[1]
+        self.thread = threading.Thread(target=self.srv.serve_forever, daemon=True)
+        self.thread.start()
+
+    def tearDown(self):
+        self.srv.shutdown()
+
+    def _url(self, path, token=None):
+        q = f"?t={token}" if token else ""
+        return f"http://127.0.0.1:{self.port}{path}{q}"
+
+    def test_requires_token(self):
+        with self.assertRaises(urllib.error.HTTPError) as cm:
+            urllib.request.urlopen(self._url("/api/snapshot"), timeout=10)
+        self.assertEqual(cm.exception.code, 403)
+
+    def test_bad_token_rejected(self):
+        with self.assertRaises(urllib.error.HTTPError) as cm:
+            urllib.request.urlopen(self._url("/api/snapshot", "wrong"), timeout=10)
+        self.assertEqual(cm.exception.code, 403)
+
+    def test_snapshot_with_token(self):
+        data = json.load(urllib.request.urlopen(self._url("/api/snapshot", self.token), timeout=10))
+        self.assertIn("groups", data)
+
+    def test_page_served(self):
+        body = urllib.request.urlopen(self._url("/", self.token), timeout=10).read()
+        self.assertIn(b"read-only share", body)
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/test_steam.py

@@ -0,0 +1,147 @@
+"""Tests for M6 Steam library & game detection (VDF parse, scan, tool filter, cache diff)."""
+
+import tempfile
+import unittest
+from pathlib import Path
+from unittest import mock
+
+from rigdoctor.core import steam
+
+_GAME_ACF = """"AppState"
+{{
+\t"appid"\t\t"{appid}"
+\t"name"\t\t"{name}"
+\t"installdir"\t\t"{installdir}"
+\t"SizeOnDisk"\t\t"{size}"
+\t"LastUpdated"\t\t"{updated}"
+}}
+"""
+
+_LIBRARYFOLDERS = """"libraryfolders"
+{{
+\t"0"
+\t{{
+\t\t"path"\t\t"{path}"
+\t\t"label"\t\t"Main"
+\t\t"apps"
+\t\t{{
+\t\t\t"570"\t\t"123"
+\t\t}}
+\t}}
+}}
+"""
+
+
+def _make_library(root: Path, games) -> Path:
+    """games: list of (appid, name, installdir, size, updated). Returns the library path."""
+    steamapps = root / "steamapps"
+    steamapps.mkdir(parents=True, exist_ok=True)
+    for appid, name, installdir, size, updated in games:
+        (steamapps / f"appmanifest_{appid}.acf").write_text(
+            _GAME_ACF.format(appid=appid, name=name, installdir=installdir, size=size, updated=updated)
+        )
+    return root
+
+
+class VdfTests(unittest.TestCase):
+    def test_parse_nested_and_pairs(self):
+        data = steam._parse_vdf(_GAME_ACF.format(
+            appid="570", name="Dota 2", installdir="dota 2 beta", size="15", updated="1700"))
+        state = data["AppState"]
+        self.assertEqual(state["appid"], "570")
+        self.assertEqual(state["name"], "Dota 2")
+        self.assertEqual(state["installdir"], "dota 2 beta")
+
+    def test_parse_handles_quotes_in_names(self):
+        acf = _GAME_ACF.format(appid="1", name="Baldur\\'s Gate 3", installdir="bg3", size="1", updated="1")
+        data = steam._parse_vdf(acf)
+        self.assertIn("Baldur", data["AppState"]["name"])
+
+    def test_parse_garbage_returns_empty(self):
+        self.assertEqual(steam._parse_vdf("not vdf at all"), {})
+
+
+class ToolFilterTests(unittest.TestCase):
+    def test_known_tool_appid(self):
+        self.assertTrue(steam.is_tool("228980", "Steamworks Common Redistributables"))
+
+    def test_proton_name_prefix(self):
+        self.assertTrue(steam.is_tool("9999999", "Proton 8.0"))
+        self.assertTrue(steam.is_tool("9999998", "Steam Linux Runtime 3.0 (sniper)"))
+
+    def test_real_game_is_not_a_tool(self):
+        self.assertFalse(steam.is_tool("570", "Dota 2"))
+
+
+class ScanTests(unittest.TestCase):
+    def test_scan_library_filters_tools(self):
+        with tempfile.TemporaryDirectory() as d:
+            lib = _make_library(Path(d), [
+                ("570", "Dota 2", "dota 2 beta", "15000000000", "1700000000"),
+                ("228980", "Steamworks Common Redistributables", "Steamworks Shared", "0", "0"),
+                ("1493710", "Proton Experimental", "Proton - Experimental", "0", "0"),
+            ])
+            games = steam.scan_library(str(lib))
+            names = {g.name for g in games}
+            self.assertEqual(names, {"Dota 2"})
+            self.assertEqual(games[0].size_bytes, 15000000000)
+
+    def test_scan_games_dedupes_and_sorts(self):
+        with tempfile.TemporaryDirectory() as d1, tempfile.TemporaryDirectory() as d2:
+            a = _make_library(Path(d1), [("10", "Zeta", "zeta", "1", "1"), ("20", "Alpha", "alpha", "1", "1")])
+            b = _make_library(Path(d2), [("20", "Alpha", "alpha", "1", "1")])  # dup appid 20
+            games = steam.scan_games([str(a), str(b)])
+            self.assertEqual([g.name for g in games], ["Alpha", "Zeta"])  # sorted, deduped
+
+
+class DiscoverTests(unittest.TestCase):
+    def test_discover_reads_libraryfolders(self):
+        with tempfile.TemporaryDirectory() as d:
+            root = Path(d) / "Steam"
+            (root / "steamapps").mkdir(parents=True)
+            extra = Path(d) / "Extra"
+            (extra / "steamapps").mkdir(parents=True)
+            (root / "steamapps" / "libraryfolders.vdf").write_text(
+                _LIBRARYFOLDERS.format(path=str(extra)))
+            with mock.patch.object(steam, "steam_roots", return_value=[root]):
+                libs = steam.discover_libraries()
+            paths = {lib.path for lib in libs}
+            self.assertIn(str(root.resolve()), paths)   # root itself
+            self.assertIn(str(extra.resolve()), paths)  # the configured extra library
+
+
+class CacheDiffTests(unittest.TestCase):
+    def _rescan(self, lib, games_file, cfg):
+        with mock.patch.object(steam, "GAMES_FILE", games_file):
+            return steam.rescan(cfg=cfg)
+
+    def test_first_scan_has_no_new_then_added_game_is_new(self):
+        with tempfile.TemporaryDirectory() as d:
+            lib = _make_library(Path(d) / "lib", [("10", "Alpha", "alpha", "1", "1")])
+            games_file = Path(d) / "games.json"
+            cfg = {"steam_libraries": [str(lib)]}
+
+            first = self._rescan(lib, games_file, cfg)
+            self.assertEqual(first.new_appids, [])  # first run flags nothing as new
+
+            # Install a second game; it should be flagged new on the next scan.
+            _make_library(lib, [("10", "Alpha", "alpha", "1", "1"), ("20", "Beta", "beta", "1", "1")])
+            second = self._rescan(lib, games_file, cfg)
+            self.assertEqual(second.new_appids, ["20"])
+            self.assertEqual({g.name for g in second.games}, {"Alpha", "Beta"})
+
+    def test_acknowledge_clears_new(self):
+        with tempfile.TemporaryDirectory() as d:
+            lib = _make_library(Path(d) / "lib", [("10", "Alpha", "alpha", "1", "1")])
+            games_file = Path(d) / "games.json"
+            cfg = {"steam_libraries": [str(lib)]}
+            self._rescan(lib, games_file, cfg)
+            _make_library(lib, [("10", "Alpha", "alpha", "1", "1"), ("20", "Beta", "beta", "1", "1")])
+            self._rescan(lib, games_file, cfg)
+            with mock.patch.object(steam, "GAMES_FILE", games_file):
+                steam.acknowledge_new()
+                self.assertEqual(steam.load_cache()["new_appids"], [])
+
+
+if __name__ == "__main__":
+    unittest.main()