diff --git a/config/bin/hyprcosmic-powermenu b/config/bin/hyprcosmic-powermenu
new file mode 100755
index 0000000..da01fdb
--- /dev/null
+++ b/config/bin/hyprcosmic-powermenu
@@ -0,0 +1,105 @@
+#!/usr/bin/bash
+#
+# Power menu for a HyprCosmic session: lock, suspend, log out, reboot, shut down.
+#
+# WHY THIS EXISTS
+# ---------------
+# Stock COSMIC puts all of these behind the power applet in cosmic-panel.
+# HyprCosmic replaces the panel with waybar, so that applet never starts and the
+# session had no exit at all -- not even a logout -- short of `systemctl reboot`
+# typed into a terminal. This is the exit. It is reached from a keybinding and
+# from the bar, and both run this same script so the two can never disagree.
+#
+# Logging out goes through cosmic-session's own D-Bus interface rather than
+# killing anything. That is the method the panel applet called, and it is the
+# only one that lets the session stop its clients in order instead of pulling
+# the compositor out from under them; see `com.system76.CosmicSession.Exit` in
+# cosmic-session/src/service.rs.
+#
+# Reboot and poweroff go to systemd directly. polkit already authorises both for
+# an active local session without a prompt, which is why no pkexec is involved.
+#
+# NO GLYPHS HERE, DELIBERATELY
+# ----------------------------
+# Every entry is a plain word. Nerd Font icons live in the Private Use Area,
+# where they are indistinguishable from each other in a diff and are silently
+# destroyed by anything that retypes rather than copies them. waybar's power
+# icon is the only glyph in this feature and it comes from generate-config.py,
+# which checks each codepoint against the installed font.
+
+set -uo pipefail
+
+SESSION_DEST=com.system76.CosmicSession
+SESSION_PATH=/com/system76/CosmicSession
+
+command -v rofi >/dev/null 2>&1 || {
+    printf 'hyprcosmic-powermenu: rofi is not installed\n' >&2
+    exit 1
+}
+
+# Errors go to a rofi dialog, not just stderr. The two ways in are a keybinding
+# and a bar click, and neither has a terminal attached to read stderr from.
+fail() {
+    printf 'hyprcosmic-powermenu: %s\n' "$*" >&2
+    rofi -e "$*" >/dev/null 2>&1 || :
+    exit 1
+}
+
+# No theme arguments, so ~/.config/rofi/config.rasi applies and this matches the
+# launcher. Icons off because these entries have none and the reserved space
+# would sit there empty.
+#
+# -no-custom is what stops a typed line from being returned as if it were a
+# choice: without it, Return on an empty filter hands back whatever was typed,
+# and the case below would fall through to no branch at all. With it, anything
+# that is not one of the offered entries is refused.
+menu() {
+    local prompt="$1"
+    shift
+    printf '%s\n' "$@" | rofi -dmenu -i -no-custom -no-show-icons -p "$prompt"
+}
+
+# Only for the three that end the session. Locking and suspending undo
+# themselves with a keypress, so a confirmation there is pure friction; logging
+# out, rebooting and shutting down each throw away every unsaved thing on the
+# desktop, and this menu is one keystroke away at all times.
+#
+# "No" is listed first so that it is the selected row when the dialog opens.
+confirm() {
+    local answer
+    answer="$(menu "$1?" "No" "Yes")" || return 1
+    [[ "$answer" == "Yes" ]]
+}
+
+logout() {
+    command -v busctl >/dev/null 2>&1 ||
+        fail "busctl is not installed, so the session cannot be asked to exit"
+
+    busctl --user call "$SESSION_DEST" "$SESSION_PATH" "$SESSION_DEST" Exit && return 0
+
+    # Reaching here means cosmic-session is not answering on the bus. Say so
+    # rather than silently doing nothing: being unable to leave the session is
+    # the exact problem this script was written for, so a dead end here is
+    # worse than a blunt instrument. loginctl is that blunt instrument, and it
+    # is named explicitly so the choice to use it is the user's.
+    fail "cosmic-session did not answer on D-Bus.
+To force the session to end, run:
+    loginctl terminate-session ${XDG_SESSION_ID:-\$XDG_SESSION_ID}"
+}
+
+choice="$(menu "Power" "Lock" "Suspend" "Log out" "Reboot" "Shut down")" || exit 0
+
+case "$choice" in
+    "Lock")      exec loginctl lock-session ;;
+    "Suspend")   exec systemctl suspend ;;
+    "Log out")   confirm "Log out"   && logout ;;
+    "Reboot")    confirm "Reboot"    && exec systemctl reboot ;;
+    "Shut down") confirm "Shut down" && exec systemctl poweroff ;;
+    "")          ;;
+    *)           fail "unrecognised choice: ${choice}" ;;
+esac
+
+# Reached only by answering "No" to a confirmation, or dismissing it. The four
+# branches that act replace this process outright, and `fail` exits on its own,
+# so nothing else arrives here -- and changing your mind is not a failure.
+exit 0
diff --git a/config/cosmic.conf b/config/cosmic.conf
index 0d09238..5a95f92 100644
--- a/config/cosmic.conf
+++ b/config/cosmic.conf
@@ -72,3 +72,16 @@ bind = $mainMod, W, exec, rofi -show window
 # Terminal, in the Hyprland idiom. Super+T also still works — cosmic-comp
 # handles System(Terminal) itself, so that binding never went dead.
 bind = $mainMod, Return, exec, cosmic-term
+
+# --- Session ------------------------------------------------------------
+#
+# The hyprcosmic profile disables cosmic-panel, and COSMIC's power applet lives
+# in that panel, so a HyprCosmic session had no logout, reboot or shutdown
+# anywhere -- the only way out was `systemctl reboot` from a terminal. This is
+# that way out. The same script backs waybar's power button, so the two cannot
+# drift apart, and it asks for confirmation before anything that ends the
+# session.
+#
+# Super+Shift+E is Hyprland's own spelling for "exit". The menu also offers
+# lock and suspend, which is why the binding is not named after logout.
+bind = $mainMod SHIFT, E, exec, hyprcosmic-powermenu
diff --git a/config/waybar/config.jsonc b/config/waybar/config.jsonc
index 327dec0..53a6b95 100644
--- a/config/waybar/config.jsonc
+++ b/config/waybar/config.jsonc
@@ -63,7 +63,8 @@
         "memory",
         "power-profiles-daemon",
         "battery",
-        "tray"
+        "tray",
+        "custom/power"
     ],
 
     "ext/workspaces": {
@@ -265,5 +266,24 @@
         "on-click": "cosmic-settings power"
     },
 
-    "tray": { "icon-size": 18, "spacing": 8 }
+    "tray": { "icon-size": 18, "spacing": 8 },
+
+    // Last on the bar, because it is the one button here that can end the
+    // session or the uptime and the far corner is the hardest place to hit by
+    // accident.
+    //
+    // It is here for the same reason "custom/swaync" is: the hyprcosmic profile
+    // disables cosmic-panel, and COSMIC's power applet lives in that panel.
+    // Without this there is no logout, reboot or shutdown anywhere in the
+    // session -- the only way out was `systemctl reboot` from a terminal.
+    //
+    // The click runs the same script as the $mainMod SHIFT E binding rather
+    // than calling systemctl here, so the confirmation step cannot be bypassed
+    // by using the mouse.
+    "custom/power": {
+        "format": "\uf011",
+        "tooltip": true,
+        "tooltip-format": "Lock, suspend, log out, reboot or shut down",
+        "on-click": "hyprcosmic-powermenu"
+    }
 }
diff --git a/config/waybar/config.jsonc.in b/config/waybar/config.jsonc.in
index 3a25c25..77c955a 100644
--- a/config/waybar/config.jsonc.in
+++ b/config/waybar/config.jsonc.in
@@ -63,7 +63,8 @@
         "memory",
         "power-profiles-daemon",
         "battery",
-        "tray"
+        "tray",
+        "custom/power"
     ],
 
     "ext/workspaces": {
@@ -265,5 +266,24 @@
         "on-click": "cosmic-settings power"
     },
 
-    "tray": { "icon-size": 18, "spacing": 8 }
+    "tray": { "icon-size": 18, "spacing": 8 },
+
+    // Last on the bar, because it is the one button here that can end the
+    // session or the uptime and the far corner is the hardest place to hit by
+    // accident.
+    //
+    // It is here for the same reason "custom/swaync" is: the hyprcosmic profile
+    // disables cosmic-panel, and COSMIC's power applet lives in that panel.
+    // Without this there is no logout, reboot or shutdown anywhere in the
+    // session -- the only way out was `systemctl reboot` from a terminal.
+    //
+    // The click runs the same script as the $mainMod SHIFT E binding rather
+    // than calling systemctl here, so the confirmation step cannot be bypassed
+    // by using the mouse.
+    "custom/power": {
+        "format": "@@POWER@@",
+        "tooltip": true,
+        "tooltip-format": "Lock, suspend, log out, reboot or shut down",
+        "on-click": "hyprcosmic-powermenu"
+    }
 }
diff --git a/config/waybar/generate-config.py b/config/waybar/generate-config.py
index b75e0a1..0e3bfe1 100755
--- a/config/waybar/generate-config.py
+++ b/config/waybar/generate-config.py
@@ -43,6 +43,7 @@ ICONS = {
     "SAVER": 0xF06C,
     "BALANCED": 0xF24E,
     "PROFILE": 0xF0E7,
+    "POWER": 0xF011,
     "BAT_00": 0xF008E,
     "BAT_10": 0xF007A,
     "BAT_20": 0xF007B,
diff --git a/config/waybar/rules.css b/config/waybar/rules.css
index d2f039c..ca55dbb 100644
--- a/config/waybar/rules.css
+++ b/config/waybar/rules.css
@@ -90,13 +90,22 @@ window#waybar {
 #memory,
 #power-profiles-daemon,
 #battery,
-#tray {
+#tray,
+#custom-power {
     padding: 0 10px;
     margin: 4px 2px;
     border-radius: 10px;
     background: @module-bg;
 }
 
+/* The only module here that is a button rather than a readout, so it is the
+ * only one that gains anything from a hover state. Colour rather than
+ * background, to match how the status colours below signal without moving
+ * anything. */
+#custom-power:hover {
+    color: @critical;
+}
+
 #clock {
     font-weight: bold;
 }
diff --git a/tools/install-assets.sh b/tools/install-assets.sh
index 405326a..1c77e0c 100755
--- a/tools/install-assets.sh
+++ b/tools/install-assets.sh
@@ -73,6 +73,7 @@ SHARED=(
     "config/waybar/rules.css:share/hyprcosmic/waybar/rules.css:644"
     "config/rofi/palette.rasi:share/hyprcosmic/rofi/palette.rasi:644"
     "config/rofi/rules.rasi:share/hyprcosmic/rofi/rules.rasi:644"
+    "config/bin/hyprcosmic-powermenu:bin/hyprcosmic-powermenu:755"
 )
 
 # The session entry point. Kept apart from SHARED because it is versioned in the