diff --git a/.gitignore b/.gitignore
index 885944c2..20bfa5b2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,4 @@
 old/
 docs/superpowers/
 .superpowers/
+result/
diff --git a/home/programs/tui/git/default.nix b/home/programs/tui/git/default.nix
index e82f566c..e86cf5df 100644
--- a/home/programs/tui/git/default.nix
+++ b/home/programs/tui/git/default.nix
@@ -17,6 +17,7 @@ in {
       "result"
       "result-*"
       ".superpowers/"
+      ".claude/"
       "docs/superpowers/"
     ];
     settings = {
diff --git a/home/system/waybar/battery-monitor.sh b/home/system/waybar/battery-monitor.sh
new file mode 100644
index 00000000..7a707772
--- /dev/null
+++ b/home/system/waybar/battery-monitor.sh
@@ -0,0 +1,104 @@
+# battery-monitor — low-battery alerts for waybar/swaync.
+# Sourced by the tests with BATTERY_MONITOR_TEST=1 (defines the functions, skips main).
+# Otherwise runs main once (triggered by the battery-monitor systemd timer).
+
+POWER_SUPPLY_DIR="${POWER_SUPPLY_DIR:-/sys/class/power_supply}"
+STATE_FILE="${BATTERY_STATE_FILE:-/tmp/battery-alert-state}"
+CRIT_ID_FILE="${BATTERY_CRIT_ID_FILE:-/tmp/battery-crit-id}"
+
+WARN_THRESHOLD=10
+CRIT_THRESHOLD=5
+
+# Pure decision. Prints "<action>:<newstate>".
+# action ∈ noop | osd_warn | crit_show | crit_clear ; state ∈ none | warn10 | crit5
+battery_decide() {
+  status=$1
+  cap=$2
+  prev=$3
+
+  if [ "$status" = "Discharging" ]; then
+    if [ "$cap" -le "$CRIT_THRESHOLD" ]; then
+      echo "crit_show:crit5"
+    elif [ "$cap" -le "$WARN_THRESHOLD" ]; then
+      if [ "$prev" = "crit5" ]; then
+        echo "crit_clear:warn10"
+      elif [ "$prev" = "warn10" ]; then
+        echo "noop:warn10"
+      else
+        echo "osd_warn:warn10"
+      fi
+    else
+      if [ "$prev" = "crit5" ]; then
+        echo "crit_clear:none"
+      else
+        echo "noop:none"
+      fi
+    fi
+  else
+    if [ "$prev" = "crit5" ]; then
+      echo "crit_clear:none"
+    else
+      echo "noop:none"
+    fi
+  fi
+}
+
+# First real battery (type == Battery, with status + capacity).
+resolve_battery() {
+  for d in "$POWER_SUPPLY_DIR"/*; do
+    [ -r "$d/type" ] || continue
+    [ "$(cat "$d/type")" = "Battery" ] || continue
+    [ -r "$d/status" ] && [ -r "$d/capacity" ] || continue
+    printf '%s' "$d"
+    return 0
+  done
+  return 1
+}
+
+show_warn_osd() {
+  waybar-osd "󰂃  Low battery · $1%"
+}
+
+show_crit_notification() {
+  cap=$1
+  id=$(cat "$CRIT_ID_FILE" 2>/dev/null || echo 0)
+  newid=$(notify-send --print-id --replace-id="$id" \
+    --urgency=critical --expire-time=0 \
+    "󰂃 Critical battery" "Battery at $cap% — plug in the charger")
+  printf '%s' "$newid" > "$CRIT_ID_FILE"
+}
+
+clear_crit_notification() {
+  id=$(cat "$CRIT_ID_FILE" 2>/dev/null || echo 0)
+  if [ "$id" != "0" ]; then
+    gdbus call --session \
+      --dest org.freedesktop.Notifications \
+      --object-path /org/freedesktop/Notifications \
+      --method org.freedesktop.Notifications.CloseNotification "$id" \
+      >/dev/null 2>&1 || true
+  fi
+  rm -f "$CRIT_ID_FILE"
+}
+
+main() {
+  dir=$(resolve_battery) || exit 0
+
+  status=$(cat "$dir/status")
+  cap=$(cat "$dir/capacity")
+  prev=$(cat "$STATE_FILE" 2>/dev/null || echo none)
+
+  result=$(battery_decide "$status" "$cap" "$prev")
+  action=${result%%:*}
+  newstate=${result##*:}
+
+  case "$action" in
+    osd_warn)   show_warn_osd "$cap" ;;
+    crit_show)  show_crit_notification "$cap" ;;
+    crit_clear) clear_crit_notification ;;
+    noop)       : ;;
+  esac
+
+  printf '%s' "$newstate" > "$STATE_FILE"
+}
+
+[ "${BATTERY_MONITOR_TEST:-}" = "1" ] || main "$@"
diff --git a/home/system/waybar/default.nix b/home/system/waybar/default.nix
index 27bb342e..22053edf 100644
--- a/home/system/waybar/default.nix
+++ b/home/system/waybar/default.nix
@@ -20,7 +20,25 @@ in {
       iw
       hyprsunset
     ]
-    ++ (with scripts; [vol-up vol-down vol-mute mic-mute bright-up bright-down nightshift-toggle focus-toggle waybar-toggle wifi-toggle bluetooth-toggle dnd-toggle output-cycle input-cycle color-pick screenshot-edit record-toggle power-cycle airplane-toggle clipboard-menu emoji-picker caffeine-toggle mic-status]);
+    ++ (with scripts; [waybar-osd battery-monitor vol-up vol-down vol-mute mic-mute bright-up bright-down nightshift-toggle focus-toggle waybar-toggle wifi-toggle bluetooth-toggle dnd-toggle output-cycle input-cycle color-pick screenshot-edit record-toggle power-cycle airplane-toggle clipboard-menu emoji-picker caffeine-toggle mic-status]);
+
+  # Poll battery level every 30s; battery-monitor no-ops when no battery exists.
+  systemd.user.services.battery-monitor = {
+    Unit.Description = "Low-battery OSD and critical notification monitor";
+    Service = {
+      Type = "oneshot";
+      ExecStart = "${scripts.battery-monitor}/bin/battery-monitor";
+    };
+  };
+
+  systemd.user.timers.battery-monitor = {
+    Unit.Description = "Poll battery level for low-battery alerts";
+    Timer = {
+      OnBootSec = "1min";
+      OnUnitActiveSec = "30s";
+    };
+    Install.WantedBy = ["timers.target"];
+  };
 
   wayland.windowManager.hyprland.settings.exec-once = [
     "waybar"
diff --git a/home/system/waybar/scripts.nix b/home/system/waybar/scripts.nix
index da71fa76..62dc1a48 100644
--- a/home/system/waybar/scripts.nix
+++ b/home/system/waybar/scripts.nix
@@ -1,10 +1,29 @@
 {pkgs}: let
+  # Canonical OSD popup: write the shared slot, signal waybar, expire after 2.5s.
+  # Packaged (runtimeInputs) so it works outside a graphical session (systemd).
+  waybar-osd = pkgs.writeShellApplication {
+    name = "waybar-osd";
+    runtimeInputs = with pkgs; [procps coreutils];
+    text = ''
+      if [ -f /tmp/waybar-osd-pid ]; then
+        kill "$(cat /tmp/waybar-osd-pid)" 2>/dev/null || true
+      fi
+      printf '%s' "$1" > /tmp/waybar-osd
+      pkill -RTMIN+8 waybar 2>/dev/null || true
+      ( sleep 2.5; rm -f /tmp/waybar-osd /tmp/waybar-osd-pid; pkill -RTMIN+8 waybar 2>/dev/null || true ) &
+      printf '%s' "$!" > /tmp/waybar-osd-pid
+    '';
+  };
+
+  # battery-monitor: low-battery alerts, run by the systemd user timer.
+  battery-monitor = pkgs.writeShellApplication {
+    name = "battery-monitor";
+    runtimeInputs = with pkgs; [waybar-osd libnotify glib coreutils];
+    text = builtins.readFile ./battery-monitor.sh;
+  };
+
   updateOsd = ''
-    [ -f /tmp/waybar-osd-pid ] && kill "$(cat /tmp/waybar-osd-pid)" 2>/dev/null
-    printf '%s' "$OSD_TEXT" > /tmp/waybar-osd
-    pkill -RTMIN+8 waybar 2>/dev/null
-    ( sleep 2.5; rm -f /tmp/waybar-osd /tmp/waybar-osd-pid; pkill -RTMIN+8 waybar 2>/dev/null ) &
-    printf '%s' "$!" > /tmp/waybar-osd-pid
+    ${waybar-osd}/bin/waybar-osd "$OSD_TEXT"
   '';
 
   volGetText = ''
@@ -46,10 +65,12 @@
   # launcher, unusable for a list, so override the geometry here.
   tofiMenu = "${pkgs.tofi}/bin/tofi --horizontal false --anchor center --width 700 --height 500 --margin-top 0 --margin-left 0 --margin-right 0 --num-results 10";
 in {
+  inherit waybar-osd battery-monitor;
+
   bluetoothScript = pkgs.writeShellScript "waybar-bluetooth" ''
     jq=${pkgs.jq}/bin/jq
     nl=$'\n'
-    # bluetoothctl bloque sans contrôleur par défaut → toujours borné par timeout.
+    # bluetoothctl hangs without a controller by default → always bounded by timeout.
     bt() { timeout 3 ${pkgs.bluez}/bin/bluetoothctl "$@" 2>/dev/null; }
 
     powered=$(bt show | awk '/Powered:/ { print $2; exit }')
@@ -331,7 +352,7 @@ in {
 
   record-toggle = pkgs.writeShellScriptBin "record-toggle" ''
     if pgrep -x wf-recorder >/dev/null; then
-      # -INT laisse wf-recorder finaliser le fichier proprement.
+      # -INT lets wf-recorder finalize the file cleanly.
       pkill -INT -x wf-recorder
       OSD_TEXT="󰕧  Recording saved"
     else
@@ -385,7 +406,7 @@ in {
   emoji-picker = pkgs.writeShellScriptBin "emoji-picker" ''
     export PATH="${pkgs.wtype}/bin:${pkgs.wl-clipboard}/bin:$PATH"
     export BEMOJI_PICKER_CMD="${tofiMenu} --prompt-text 'emoji: '"
-    # -t tape l'emoji (wtype), -c le copie aussi.
+    # -t types the emoji (wtype), -c also copies it.
     exec ${pkgs.bemoji}/bin/bemoji -t -c
   '';
 
diff --git a/home/system/waybar/settings.nix b/home/system/waybar/settings.nix
index 3bb3790e..cd40b219 100644
--- a/home/system/waybar/settings.nix
+++ b/home/system/waybar/settings.nix
@@ -8,7 +8,6 @@
 }: let
   gaps-out = config.theme.gaps-out;
   c = config.lib.stylix.colors;
-  hasBattery = config.var.hasBattery or false;
 in {
   programs.waybar.settings = [
     {
@@ -16,9 +15,7 @@ in {
       position = "top";
       height = config.theme.bar-height;
       margin = "${toString gaps-out} ${toString gaps-out} 0";
-      modules-center =
-        ["custom/osd" "custom/osd-sep" "clock" "tray" "hyprland/workspaces" "custom/network" "custom/bluetooth"]
-        ++ lib.optional hasBattery "battery";
+      modules-center = ["custom/osd" "custom/osd-sep" "clock" "tray" "hyprland/workspaces" "custom/network" "custom/bluetooth" "battery"];
 
       # ── Modules ─────────────────────────────────────────────────────────
 
@@ -34,7 +31,6 @@ in {
       };
 
       battery = {
-        bat = "BAT1";
         interval = 20;
         full-at = 100;
         tooltip = true;
diff --git a/home/system/waybar/tests/battery-decide.test.sh b/home/system/waybar/tests/battery-decide.test.sh
new file mode 100644
index 00000000..32127fbe
--- /dev/null
+++ b/home/system/waybar/tests/battery-decide.test.sh
@@ -0,0 +1,34 @@
+#!/usr/bin/env bash
+# Unit tests for battery_decide. Run: bash home/system/waybar/tests/battery-decide.test.sh
+set -u
+
+DIR="$(cd "$(dirname "$0")/.." && pwd)"
+BATTERY_MONITOR_TEST=1 . "$DIR/battery-monitor.sh"
+
+fail=0
+check() {
+  desc=$1 status=$2 cap=$3 prev=$4 expected=$5
+  got=$(battery_decide "$status" "$cap" "$prev")
+  if [ "$got" = "$expected" ]; then
+    printf 'ok   - %s\n' "$desc"
+  else
+    printf 'FAIL - %s: expected %s, got %s\n' "$desc" "$expected" "$got"
+    fail=1
+  fi
+}
+
+check "discharging 4% fresh -> crit"                Discharging 4   none   crit_show:crit5
+check "discharging 4% already crit -> refresh"      Discharging 4   crit5  crit_show:crit5
+check "discharging 5% boundary -> crit"             Discharging 5   none   crit_show:crit5
+check "discharging 8% fresh -> warn osd"            Discharging 8   none   osd_warn:warn10
+check "discharging 8% already warned -> noop"       Discharging 8   warn10 noop:warn10
+check "discharging 8% recovering from crit -> clear+warn" Discharging 8 crit5 crit_clear:warn10
+check "discharging 10% boundary -> warn"            Discharging 10  none   osd_warn:warn10
+check "discharging 11% -> noop none"                Discharging 11  none   noop:none
+check "discharging 12% rearm from warn -> none"     Discharging 12  warn10 noop:none
+check "discharging 40% recover from crit -> clear"  Discharging 40  crit5  crit_clear:none
+check "charging 4% from crit -> clear"              Charging    4   crit5  crit_clear:none
+check "charging 8% from warn -> none"               Charging    8   warn10 noop:none
+check "full 100% -> noop none"                      Full        100 none   noop:none
+
+exit $fail
diff --git a/hosts/laptop/variables.nix b/hosts/laptop/variables.nix
index 48128572..c703f538 100644
--- a/hosts/laptop/variables.nix
+++ b/hosts/laptop/variables.nix
@@ -26,8 +26,6 @@
 
     autoUpgrade = false;
     autoGarbageCollector = true;
-
-    hasBattery = true;
   };
 
   # DON'T TOUCH THIS
diff --git a/hosts/work/variables.nix b/hosts/work/variables.nix
index f8569301..9247e0c5 100644
--- a/hosts/work/variables.nix
+++ b/hosts/work/variables.nix
@@ -26,8 +26,6 @@
 
     autoUpgrade = false;
     autoGarbageCollector = true;
-
-    hasBattery = false;
   };
 
   # DON'T TOUCH THIS
diff --git a/todo b/todo
index 66c13fa4..37770b89 100644
--- a/todo
+++ b/todo
@@ -7,4 +7,3 @@
 - hide bluetooth icon in tray
 - screenshots
 - enlever notif flake nvf
-