diff --git a/README.md b/README.md
index 7007edf..bf775d3 100644
--- a/README.md
+++ b/README.md
@@ -136,7 +136,7 @@ docs/           Settings reference, and the design specs behind the work
 
 ## Tests
 
-158 of them, under `tests/`. Run the lot, or a subset by pattern:
+159 of them, under `tests/`. Run the lot, or a subset by pattern:
 
 ```sh
 panama test           # everything
diff --git a/config/dot/hypr/autostart.lua b/config/dot/hypr/autostart.lua
index f495b77..032502e 100644
--- a/config/dot/hypr/autostart.lua
+++ b/config/dot/hypr/autostart.lua
@@ -91,8 +91,28 @@ hl.on("hyprland.start", function()
     -- session on its own. Starting it here as well would give you two trays.
 end)
 
+-- Tear down what the start handler brought up.
+--
+-- This stopped `hyprland-session.target`, which does not exist on Fedora --
+-- systemctl reports "Unit not found" and the handler achieves nothing. The
+-- units started above are not children of the compositor, so nothing else
+-- stopped them either: hyprpaper, hypridle, vicinae and the polkit agent kept
+-- running after logout, and each one Requires=graphical-session.target, so
+-- that target stayed active with no session behind it.
+--
+-- The next login then failed. Both uwsm and gnome-session refuse to start into
+-- a session that is already running ("A compositor or graphical-session*
+-- target is already active!"), so "Hyprland (uwsm-managed)" and GNOME both
+-- bounced straight back to the login screen while plain Hyprland -- which
+-- makes no such check -- kept working. The desktop appeared to be the only one
+-- that functioned, when it was the one leaving the mess.
+--
+-- Stopping graphical-session.target is enough on its own: every unit above is
+-- PartOf= it, so they come down with it, and it carries StopWhenUnneeded=yes.
+-- It is stopped rather than the units listed individually so that a unit added
+-- to the start handler later cannot be forgotten here.
 hl.on("hyprland.shutdown", function()
-    hl.exec_cmd("systemctl --user stop hyprland-session.target")
+    hl.exec_cmd("systemctl --user stop graphical-session.target")
 end)
 
 return true
diff --git a/config/local/share/systemd/user/panama-crash-watch.service b/config/local/share/systemd/user/panama-crash-watch.service
index 2567b0b..4f23f4e 100644
--- a/config/local/share/systemd/user/panama-crash-watch.service
+++ b/config/local/share/systemd/user/panama-crash-watch.service
@@ -5,6 +5,14 @@ Documentation=https://github.com/gibbyb/Panama
 # the same reason as every other Panama unit: graphical-session.target is
 # active under GNOME too, and this reports through the Hyprland shell's
 # notification server.
+#
+# PartOf, so it stops with the session that started it. Without it this
+# outlived logout -- a journal follower per login, accumulating -- and its
+# "once per program per session" dedup silently became once per boot, which is
+# the opposite of what it promises: the second crash of the day went unreported
+# because the first session had already spoken.
+PartOf=graphical-session.target
+After=graphical-session.target
 
 [Service]
 Type=simple
diff --git a/tests/hypr/session-teardown-contract b/tests/hypr/session-teardown-contract
new file mode 100755
index 0000000..d5446b1
--- /dev/null
+++ b/tests/hypr/session-teardown-contract
@@ -0,0 +1,79 @@
+#!/usr/bin/env bash
+
+# What the session starts, the session must stop.
+#
+# autostart.lua starts about ten user units on hyprland.start. None of them is
+# a child of the compositor, so when Hyprland exits they keep running -- and
+# each one carries Requires=graphical-session.target, so that target stays
+# active with no session behind it.
+#
+# The shutdown handler was supposed to prevent exactly that, and did not: it
+# stopped `hyprland-session.target`, a unit Fedora does not ship. systemctl
+# reports "Unit not found" and exits, the handler reports nothing, and the
+# stale session survives to the login screen.
+#
+# The symptom was not a broken Hyprland. It was that "Hyprland (uwsm-managed)"
+# and GNOME both bounced back to the login screen -- both refuse to start into
+# a session that is already running -- while plain Hyprland, which makes no
+# such check, kept working. The one session that appeared healthy was the one
+# doing the damage.
+#
+# Pinned here because the failure is silent in both directions: a handler that
+# stops nothing looks identical to one that works, until the next login.
+
+set -uo pipefail
+
+repo_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)"
+autostart="$repo_dir/config/dot/hypr/autostart.lua"
+
+findings=()
+note() { findings+=("$1"); }
+
+[[ -r "$autostart" ]] || { printf 'session teardown contract: no autostart.lua\n' >&2; exit 1; }
+
+# Comments stripped: the header above the handler explains the whole bug at
+# length, and matching that would be matching documentation rather than code.
+uncommented() { grep -vE '^\s*--' "$autostart"; }
+
+shutdown_body="$(uncommented | sed -n '/hl\.on("hyprland\.shutdown"/,/^end)/p')"
+
+[[ -n "$shutdown_body" ]] \
+    || note 'there is no hyprland.shutdown handler, so nothing tears the session down'
+
+# ── It must stop something that exists ──────────────────────────────────────
+
+grep -q 'hyprland-session\.target' <<<"$shutdown_body" \
+    && note 'the shutdown handler stops hyprland-session.target, which Fedora does not ship -- it is a no-op'
+
+grep -q 'stop graphical-session\.target' <<<"$shutdown_body" \
+    || note 'the shutdown handler does not stop graphical-session.target, so the units outlive the session'
+
+# ── The mechanism it relies on ──────────────────────────────────────────────
+#
+# Stopping the target only takes the units with it while they are PartOf= it.
+# A unit shipped without that line would survive the teardown and hold the
+# target back up, which is the original bug wearing a different hat.
+
+units_dir="$repo_dir/config/local/share/systemd/user"
+if [[ -d "$units_dir" ]]; then
+    for unit in "$units_dir"/*.service; do
+        [[ -e "$unit" ]] || continue
+        name="$(basename "$unit")"
+
+        # Only the ones the session starts and expects to outlive nothing. A
+        # oneshot notifier exits on its own and needs no teardown.
+        grep -q "start .*$name" "$autostart" || continue
+        grep -qE '^\s*Type\s*=\s*oneshot' "$unit" && continue
+
+        grep -qE '^\s*PartOf\s*=.*graphical-session\.target' "$unit" \
+            || note "$name is started by the session but is not PartOf graphical-session.target, so it survives logout"
+    done
+fi
+
+if (( ${#findings[@]} > 0 )); then
+    printf 'session teardown contract: %d finding(s)\n' "${#findings[@]}" >&2
+    printf '  - %s\n' "${findings[@]}" >&2
+    exit 1
+fi
+
+printf 'session teardown contract: PASS\n'