diff --git a/test/shell.d/bar-icon-geometry-test.sh b/test/shell.d/bar-icon-geometry-test.sh
index cbdd8da3..1bfcdf0c 100644
--- a/test/shell.d/bar-icon-geometry-test.sh
+++ b/test/shell.d/bar-icon-geometry-test.sh
@@ -4,10 +4,7 @@ set -euo pipefail
 
 source "$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)/base-test.sh"
 
-if [[ -z ${WAYLAND_DISPLAY:-} ]]; then
-  pass "no Wayland compositor; skipping bar icon geometry test"
-  exit 0
-fi
+require_compositor "bar icon geometry test"
 
 if ! command -v quickshell >/dev/null 2>&1; then
   pass "quickshell not installed; skipping bar icon geometry test"
diff --git a/test/shell.d/bar-widget-contract-test.sh b/test/shell.d/bar-widget-contract-test.sh
index 5d985680..95fd52b9 100755
--- a/test/shell.d/bar-widget-contract-test.sh
+++ b/test/shell.d/bar-widget-contract-test.sh
@@ -18,10 +18,7 @@ cleanup() {
 }
 trap cleanup EXIT
 
-if [[ -z ${WAYLAND_DISPLAY:-} ]]; then
-  pass "no Wayland compositor; skipping bar widget contract test"
-  exit 0
-fi
+require_compositor "bar widget contract test"
 
 if ! command -v quickshell >/dev/null 2>&1; then
   pass "quickshell not installed; skipping bar widget contract test"
diff --git a/test/shell.d/base-test.sh b/test/shell.d/base-test.sh
index 7bb019a7..9de42cf3 100644
--- a/test/shell.d/base-test.sh
+++ b/test/shell.d/base-test.sh
@@ -29,6 +29,53 @@ require_command() {
   command -v "$command" >/dev/null || fail "required command is available: $command"
 }
 
+# WAYLAND_DISPLAY proves the variable was inherited, not that the compositor
+# answers. Sandboxes pass the environment through while blocking
+# $XDG_RUNTIME_DIR, so Quickshell clears a bare variable check and then aborts
+# inside QGuiApplication, before any QML loads: a core dump per launch where a
+# skip belonged. Probe the socket, then Hyprland itself, since a compositor that
+# died mid-session can leave its socket behind.
+compositor_reachable() {
+  local socket=${WAYLAND_DISPLAY:-}
+
+  [[ -n $socket ]] || return 1
+  [[ $socket == /* ]] || socket=${XDG_RUNTIME_DIR:-}/$socket
+  [[ -S $socket ]] || return 1
+
+  # A compositor that died can leave its socket behind, so ask Hyprland whether
+  # it is still answering. Only when it can be asked: hyprctl needs
+  # HYPRLAND_INSTANCE_SIGNATURE, and treating a missing signature as a dead
+  # compositor would skip tests that would have run fine.
+  [[ -n ${HYPRLAND_INSTANCE_SIGNATURE:-} ]] || return 0
+
+  # Hyprland can miss a query while it reconfigures outputs, and one miss is not
+  # a dead compositor; retry the way omarchy-launch-shell does rather than
+  # discard a whole file's runtime coverage. Only a leftover socket gets this
+  # far, so the waiting is rare.
+  local attempt
+  for attempt in 1 2 3; do
+    hyprctl -j monitors >/dev/null 2>&1 && return 0
+    (( attempt < 3 )) && sleep 0.5
+  done
+
+  return 1
+}
+
+require_compositor() {
+  local description="$1"
+
+  if compositor_reachable; then
+    # No probe outruns a compositor that dies mid-run, and Quickshell leaves
+    # through qFatal() when its connection drops. Keep that abort from writing a
+    # core; the test still fails, just without the debris.
+    ulimit -c 0 2>/dev/null || true
+    return 0
+  fi
+
+  pass "no Wayland compositor; skipping $description"
+  exit 0
+}
+
 run_node_test() {
   require_command node
 
diff --git a/test/shell.d/button-border-stability-test.sh b/test/shell.d/button-border-stability-test.sh
index 6a1b9eee..a120f8ef 100644
--- a/test/shell.d/button-border-stability-test.sh
+++ b/test/shell.d/button-border-stability-test.sh
@@ -17,10 +17,7 @@ assert(
 )
 JS
 
-if [[ -z ${WAYLAND_DISPLAY:-} ]]; then
-  pass "no Wayland compositor; skipping Button hover geometry runtime test"
-  exit 0
-fi
+require_compositor "Button hover geometry runtime test"
 
 if ! command -v quickshell >/dev/null 2>&1; then
   pass "quickshell not installed; skipping Button hover geometry runtime test"
diff --git a/test/shell.d/compositor-guard-test.sh b/test/shell.d/compositor-guard-test.sh
new file mode 100644
index 00000000..d7525a12
--- /dev/null
+++ b/test/shell.d/compositor-guard-test.sh
@@ -0,0 +1,101 @@
+#!/bin/bash
+
+set -euo pipefail
+
+source "$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)/base-test.sh"
+
+require_command python3
+
+test_dir=$(mktemp -d)
+trap 'rm -rf "$test_dir"' EXIT
+
+runtime_dir="$test_dir/run"
+stub_bin="$test_dir/bin"
+mkdir -p "$runtime_dir" "$stub_bin"
+
+# A bound AF_UNIX socket outlives the process that bound it, which is exactly the
+# corpse a dead compositor leaves behind.
+python3 -c 'import socket, sys; socket.socket(socket.AF_UNIX).bind(sys.argv[1])' "$runtime_dir/wayland-1"
+
+attempts_log="$test_dir/hyprctl-attempts"
+
+stub_hyprctl() {
+  : >"$attempts_log"
+  cat >"$stub_bin/hyprctl" <<STUB
+#!/bin/bash
+echo asked >>"$attempts_log"
+exit $1
+STUB
+  chmod +x "$stub_bin/hyprctl"
+}
+
+# Answers only from the second query on, the way Hyprland behaves while it is
+# busy reconfiguring outputs.
+stub_flaky_hyprctl() {
+  : >"$attempts_log"
+  cat >"$stub_bin/hyprctl" <<STUB
+#!/bin/bash
+echo asked >>"$attempts_log"
+(( \$(grep -c asked "$attempts_log") > 1 ))
+STUB
+  chmod +x "$stub_bin/hyprctl"
+}
+
+attempts() {
+  grep -c asked "$attempts_log" || true
+}
+
+# The guard exits the shell it runs in, so run it in a child and report back what
+# it did: the skip line, or the core limit it left behind for Quickshell.
+run_guard() {
+  env "$@" PATH="$stub_bin:$PATH" bash -c '
+    source "$1/base-test.sh"
+    ulimit -c unlimited 2>/dev/null || true
+    require_compositor "sample runtime test"
+    printf "launched with core limit %s\n" "$(ulimit -c)"
+  ' bash "$SHELL_TEST_DIR" 2>&1 || printf 'guard exited %s\n' "$?"
+}
+
+skipped="ok - no Wayland compositor; skipping sample runtime test"
+
+output=$(run_guard -u WAYLAND_DISPLAY XDG_RUNTIME_DIR="$runtime_dir")
+[[ $output == "$skipped" ]] || fail "guard skips without a display" "$output"
+pass "guard skips without a display"
+
+# The sandbox shape from the bug report: the variable comes through, the runtime
+# directory does not.
+output=$(run_guard WAYLAND_DISPLAY=wayland-1 XDG_RUNTIME_DIR="$test_dir/blocked")
+[[ $output == "$skipped" ]] || fail "guard skips when the socket is unreachable" "$output"
+pass "guard skips when the socket is unreachable"
+
+# Hyprland can miss a single query mid-reconfigure, so only a compositor that
+# stays silent counts as gone.
+stub_hyprctl 1
+output=$(run_guard WAYLAND_DISPLAY=wayland-1 XDG_RUNTIME_DIR="$runtime_dir" HYPRLAND_INSTANCE_SIGNATURE=test)
+[[ $output == "$skipped" ]] || fail "guard skips when the compositor stopped answering" "$output"
+pass "guard skips when the compositor stopped answering"
+
+[[ $(attempts) == 3 ]] || fail "guard retries a silent compositor before giving up" "asked $(attempts) times"
+pass "guard retries a silent compositor before giving up"
+
+stub_flaky_hyprctl
+output=$(run_guard WAYLAND_DISPLAY=wayland-1 XDG_RUNTIME_DIR="$runtime_dir" HYPRLAND_INSTANCE_SIGNATURE=test)
+[[ $output == "launched with core limit 0" ]] || fail "guard rides out a missed query" "$output"
+pass "guard rides out a missed query"
+
+# Without a signature there is nothing to ask, and a live socket is all the
+# evidence there is: run rather than skip real coverage.
+stub_hyprctl 1
+output=$(run_guard -u HYPRLAND_INSTANCE_SIGNATURE WAYLAND_DISPLAY=wayland-1 XDG_RUNTIME_DIR="$runtime_dir")
+[[ $output == "launched with core limit 0" ]] || fail "guard runs when hyprctl cannot be asked" "$output"
+pass "guard runs when hyprctl cannot be asked"
+
+[[ $(attempts) == 0 ]] || fail "guard leaves hyprctl alone without a signature" "asked $(attempts) times"
+pass "guard leaves hyprctl alone without a signature"
+
+# Quickshell aborts if the compositor disappears mid-run, so the tests it is
+# about to launch must not be able to dump core.
+stub_hyprctl 0
+output=$(run_guard WAYLAND_DISPLAY=wayland-1 XDG_RUNTIME_DIR="$runtime_dir" HYPRLAND_INSTANCE_SIGNATURE=test)
+[[ $output == "launched with core limit 0" ]] || fail "guard runs with core dumps disabled" "$output"
+pass "guard runs with core dumps disabled"
diff --git a/test/shell.d/indicator-contract-test.sh b/test/shell.d/indicator-contract-test.sh
index e47d90c2..06f3f9cf 100755
--- a/test/shell.d/indicator-contract-test.sh
+++ b/test/shell.d/indicator-contract-test.sh
@@ -18,10 +18,7 @@ cleanup() {
 }
 trap cleanup EXIT
 
-if [[ -z ${WAYLAND_DISPLAY:-} ]]; then
-  pass "no Wayland compositor; skipping QML contract test"
-  exit 0
-fi
+require_compositor "QML contract test"
 
 if ! command -v quickshell >/dev/null 2>&1; then
   pass "quickshell not installed; skipping QML contract test"
diff --git a/test/shell.d/lock-fingerprint-indicator-test.sh b/test/shell.d/lock-fingerprint-indicator-test.sh
index 89c3db28..fef29783 100755
--- a/test/shell.d/lock-fingerprint-indicator-test.sh
+++ b/test/shell.d/lock-fingerprint-indicator-test.sh
@@ -18,10 +18,7 @@ cleanup() {
 }
 trap cleanup EXIT
 
-if [[ -z ${WAYLAND_DISPLAY:-} ]]; then
-  pass "no Wayland compositor; skipping lock fingerprint indicator test"
-  exit 0
-fi
+require_compositor "lock fingerprint indicator test"
 
 if ! command -v quickshell >/dev/null 2>&1; then
   pass "quickshell not installed; skipping lock fingerprint indicator test"
diff --git a/test/shell.d/lock-password-overflow-test.sh b/test/shell.d/lock-password-overflow-test.sh
index 916a1b23..5541882a 100755
--- a/test/shell.d/lock-password-overflow-test.sh
+++ b/test/shell.d/lock-password-overflow-test.sh
@@ -18,10 +18,7 @@ cleanup() {
 }
 trap cleanup EXIT
 
-if [[ -z ${WAYLAND_DISPLAY:-} ]]; then
-  pass "no Wayland compositor; skipping lock password overflow test"
-  exit 0
-fi
+require_compositor "lock password overflow test"
 
 if ! command -v quickshell >/dev/null 2>&1; then
   pass "quickshell not installed; skipping lock password overflow test"
diff --git a/test/shell.d/manifest-entrypoints-test.sh b/test/shell.d/manifest-entrypoints-test.sh
index b8b91ce1..0172aa84 100755
--- a/test/shell.d/manifest-entrypoints-test.sh
+++ b/test/shell.d/manifest-entrypoints-test.sh
@@ -18,10 +18,7 @@ cleanup() {
 }
 trap cleanup EXIT
 
-if [[ -z ${WAYLAND_DISPLAY:-} ]]; then
-  pass "no Wayland compositor; skipping manifest entrypoint load test"
-  exit 0
-fi
+require_compositor "manifest entrypoint load test"
 
 if ! command -v quickshell >/dev/null 2>&1; then
   pass "quickshell not installed; skipping manifest entrypoint load test"
diff --git a/test/shell.d/plugin-registry-contract-test.sh b/test/shell.d/plugin-registry-contract-test.sh
index 8c073381..38964043 100755
--- a/test/shell.d/plugin-registry-contract-test.sh
+++ b/test/shell.d/plugin-registry-contract-test.sh
@@ -18,10 +18,7 @@ cleanup() {
 }
 trap cleanup EXIT
 
-if [[ -z ${WAYLAND_DISPLAY:-} ]]; then
-  pass "no Wayland compositor; skipping plugin registry contract test"
-  exit 0
-fi
+require_compositor "plugin registry contract test"
 
 if ! command -v quickshell >/dev/null 2>&1; then
   pass "quickshell not installed; skipping plugin registry contract test"
diff --git a/test/shell.d/pointer-move-gate-test.sh b/test/shell.d/pointer-move-gate-test.sh
index 1a4192cf..048f5822 100644
--- a/test/shell.d/pointer-move-gate-test.sh
+++ b/test/shell.d/pointer-move-gate-test.sh
@@ -51,10 +51,7 @@ assert(
 )
 JS
 
-if [[ -z ${WAYLAND_DISPLAY:-} ]]; then
-  pass "no Wayland compositor; skipping pointer movement gate runtime test"
-  exit 0
-fi
+require_compositor "pointer movement gate runtime test"
 
 if ! command -v quickshell >/dev/null 2>&1; then
   pass "quickshell not installed; skipping pointer movement gate runtime test"
diff --git a/test/shell.d/runtime-smoke-test.sh b/test/shell.d/runtime-smoke-test.sh
index 42d9746f..f9e52bfd 100755
--- a/test/shell.d/runtime-smoke-test.sh
+++ b/test/shell.d/runtime-smoke-test.sh
@@ -17,10 +17,7 @@ cleanup() {
 }
 trap cleanup EXIT
 
-if [[ -z ${WAYLAND_DISPLAY:-} ]]; then
-  pass "no Wayland compositor; skipping shell runtime smoke test"
-  exit 0
-fi
+require_compositor "shell runtime smoke test"
 
 if ! command -v quickshell >/dev/null 2>&1; then
   pass "quickshell not installed; skipping shell runtime smoke test"
diff --git a/test/shell.d/screenshot-sanity-test.sh b/test/shell.d/screenshot-sanity-test.sh
index d2fd24b2..636642ed 100755
--- a/test/shell.d/screenshot-sanity-test.sh
+++ b/test/shell.d/screenshot-sanity-test.sh
@@ -18,10 +18,7 @@ cleanup() {
 }
 trap cleanup EXIT
 
-if [[ -z ${WAYLAND_DISPLAY:-} ]]; then
-  pass "no Wayland compositor; skipping screenshot sanity test"
-  exit 0
-fi
+require_compositor "screenshot sanity test"
 
 if ! command -v quickshell >/dev/null 2>&1; then
   pass "quickshell not installed; skipping screenshot sanity test"
diff --git a/test/shell.d/tray-menu-test.sh b/test/shell.d/tray-menu-test.sh
index 1b2fba92..514c174c 100644
--- a/test/shell.d/tray-menu-test.sh
+++ b/test/shell.d/tray-menu-test.sh
@@ -22,10 +22,7 @@ cleanup() {
 }
 trap cleanup EXIT
 
-if [[ -z ${WAYLAND_DISPLAY:-} ]]; then
-  pass "no Wayland compositor; skipping tray menu activation test"
-  exit 0
-fi
+require_compositor "tray menu activation test"
 
 if ! command -v quickshell >/dev/null 2>&1; then
   pass "quickshell not installed; skipping tray menu activation test"