diff --git a/bin/omarchy-install-and-launch b/bin/omarchy-install-and-launch
index 53bbfbc9..2a7e547c 100755
--- a/bin/omarchy-install-and-launch
+++ b/bin/omarchy-install-and-launch
@@ -16,6 +16,12 @@ fi
 printf -v install_message '%q' "Installing ${name}..."
 printf -v desktop_id_arg '%q' "$desktop_id"
 
+# The list has to reach omarchy-pkg-add as several words, so each word is quoted
+# rather than the whole string; -d '' reads past newlines and always ends at EOF.
+read -r -d '' -a package_list <<<"$packages" || true
+printf -v packages_arg '%q ' "${package_list[@]}"
+packages_arg="${packages_arg% }"
+
 # The subshell keeps & from backgrounding the package installation too.
 exec omarchy-launch-floating-terminal-with-presentation \
-  "echo ${install_message}; omarchy-pkg-add ${packages} && (setsid uwsm-app -- gtk-launch ${desktop_id_arg} >/dev/null 2>&1 &)"
+  "echo ${install_message}; omarchy-pkg-add ${packages_arg} && (setsid uwsm-app -- gtk-launch ${desktop_id_arg} >/dev/null 2>&1 &)"
diff --git a/bin/omarchy-install-app b/bin/omarchy-install-app
index bae90897..bee13e61 100755
--- a/bin/omarchy-install-app
+++ b/bin/omarchy-install-app
@@ -12,4 +12,13 @@ if [[ -z $name || -z $packages ]]; then
   exit 1
 fi
 
-exec omarchy-launch-floating-terminal-with-presentation "echo 'Installing ${name}...'; omarchy-pkg-add ${packages}"
+printf -v install_message '%q' "Installing ${name}..."
+
+# The list has to reach omarchy-pkg-add as several words, so each word is quoted
+# rather than the whole string; -d '' reads past newlines and always ends at EOF.
+read -r -d '' -a package_list <<<"$packages" || true
+printf -v packages_arg '%q ' "${package_list[@]}"
+packages_arg="${packages_arg% }"
+
+exec omarchy-launch-floating-terminal-with-presentation \
+  "echo ${install_message}; omarchy-pkg-add ${packages_arg}"
diff --git a/bin/omarchy-install-font b/bin/omarchy-install-font
index 6f68892e..8811ba48 100755
--- a/bin/omarchy-install-font
+++ b/bin/omarchy-install-font
@@ -13,5 +13,9 @@ if [[ -z $name || -z $package || -z $family ]]; then
   exit 1
 fi
 
+printf -v install_message '%q' "Installing ${name}..."
+printf -v package_arg '%q' "$package"
+printf -v family_arg '%q' "$family"
+
 exec omarchy-launch-floating-terminal-with-presentation \
-  "echo 'Installing ${name}...'; omarchy-pkg-add ${package} && sleep 2 && omarchy-font-set '${family}'"
+  "echo ${install_message}; omarchy-pkg-add ${package_arg} && sleep 2 && omarchy-font-set ${family_arg}"
diff --git a/test/shell.d/desktop-entry-launch-test.sh b/test/shell.d/desktop-entry-launch-test.sh
index 7e6f374f..c6014b10 100644
--- a/test/shell.d/desktop-entry-launch-test.sh
+++ b/test/shell.d/desktop-entry-launch-test.sh
@@ -17,6 +17,11 @@ printf 'pkg:%s\n' "$*" >>"$OMARCHY_TEST_LOG"
 exit "${OMARCHY_TEST_PKG_STATUS:-0}"
 SH
 
+cat >"$mock_bin/omarchy-font-set" <<'SH'
+#!/bin/bash
+printf 'font:%s\n' "$*" >>"$OMARCHY_TEST_LOG"
+SH
+
 for command in omarchy-pkg-aur-add omarchy-install-emacs omazed omarchy-theme-set-vscode omarchy-install-gaming-gpu-lib32; do
   cat >"$mock_bin/$command" <<'SH'
 #!/bin/bash
@@ -97,3 +102,136 @@ if grep -q '^launch:' "$OMARCHY_TEST_LOG"; then
   fail "generic installer does not launch after package installation failure"
 fi
 pass "generic installer does not launch after package installation failure"
+
+run_presentation() {
+  bash -c "sleep() { :; }; $(<"$OMARCHY_TEST_PRESENTATION")"
+}
+
+bash "$ROOT/bin/omarchy-install-app" "LM Studio" "lmstudio-bin"
+presentation_command=$(<"$OMARCHY_TEST_PRESENTATION")
+[[ $presentation_command == *'echo Installing\ LM\ Studio...;'* ]] ||
+  fail "install-app shell-quotes the display name" "$presentation_command"
+[[ $presentation_command == *'omarchy-pkg-add lmstudio-bin'* ]] ||
+  fail "install-app still passes the package list through" "$presentation_command"
+pass "install-app shell-quotes the display name"
+
+bash "$ROOT/bin/omarchy-install-app" "Example App" "alpha beta"
+presentation_command=$(<"$OMARCHY_TEST_PRESENTATION")
+[[ $presentation_command == 'echo Installing\ Example\ App...; omarchy-pkg-add alpha beta' ]] ||
+  fail "install-app builds the presentation command with no stray argument" "$presentation_command"
+: >"$OMARCHY_TEST_LOG"
+run_presentation
+grep -Fxq 'pkg:alpha beta' "$OMARCHY_TEST_LOG" ||
+  fail "install-app passes every package to the package helper"
+pass "install-app passes every package to the package helper"
+
+bash "$ROOT/bin/omarchy-install-app" "Foo's App" "alpha"
+presentation_command=$(<"$OMARCHY_TEST_PRESENTATION")
+quoted_app_message="echo $(printf '%q' "Installing Foo's App...");"
+[[ $presentation_command == "$quoted_app_message"* ]] ||
+  fail "install-app shell-quotes an apostrophe in the display name" "$presentation_command"
+: >"$OMARCHY_TEST_LOG"
+run_presentation >"$test_tmp/app-apostrophe.out"
+grep -Fxq 'pkg:alpha' "$OMARCHY_TEST_LOG" ||
+  fail "install-app still installs when the display name has an apostrophe"
+pass "install-app still installs when the display name has an apostrophe"
+
+bash "$ROOT/bin/omarchy-install-app" "a'; echo PWNED; echo '" "alpha"
+: >"$OMARCHY_TEST_LOG"
+run_presentation >"$test_tmp/app-inject.out"
+if grep -Fxq 'PWNED' "$test_tmp/app-inject.out"; then
+  fail "install-app does not run extra commands from a quote in the display name" "$(<"$test_tmp/app-inject.out")"
+fi
+grep -Fxq 'pkg:alpha' "$OMARCHY_TEST_LOG" ||
+  fail "install-app still installs after quoting a hostile display name"
+pass "install-app does not run extra commands from a quote in the display name"
+
+bash "$ROOT/bin/omarchy-install-font" "Cascadia Mono" "ttf-cascadia-mono-nerd" "CaskaydiaMono Nerd Font"
+presentation_command=$(<"$OMARCHY_TEST_PRESENTATION")
+[[ $presentation_command == *'echo Installing\ Cascadia\ Mono...;'* ]] ||
+  fail "install-font shell-quotes the display name" "$presentation_command"
+[[ $presentation_command == *'omarchy-font-set CaskaydiaMono\ Nerd\ Font'* ]] ||
+  fail "install-font shell-quotes a font family with spaces" "$presentation_command"
+: >"$OMARCHY_TEST_LOG"
+run_presentation
+grep -Fxq 'pkg:ttf-cascadia-mono-nerd' "$OMARCHY_TEST_LOG" ||
+  fail "install-font installs the font package"
+grep -Fxq 'font:CaskaydiaMono Nerd Font' "$OMARCHY_TEST_LOG" ||
+  fail "install-font passes the family name through as one argument"
+pass "install-font shell-quotes the display name and family"
+
+bash "$ROOT/bin/omarchy-install-font" "Foo's App" "alpha" "Foo's Font"
+: >"$OMARCHY_TEST_LOG"
+run_presentation >"$test_tmp/font-apostrophe.out"
+grep -Fxq 'pkg:alpha' "$OMARCHY_TEST_LOG" ||
+  fail "install-font still installs when the display name has an apostrophe"
+grep -Fxq "font:Foo's Font" "$OMARCHY_TEST_LOG" ||
+  fail "install-font still sets the family when it has an apostrophe"
+pass "install-font still installs when the name or family has an apostrophe"
+
+bash "$ROOT/bin/omarchy-install-font" "a'; echo PWNED; echo '" "alpha" "a'; echo PWNED; echo '"
+: >"$OMARCHY_TEST_LOG"
+run_presentation >"$test_tmp/font-inject.out"
+if grep -Fxq 'PWNED' "$test_tmp/font-inject.out"; then
+  fail "install-font does not run extra commands from a quote in the name or family" "$(<"$test_tmp/font-inject.out")"
+fi
+grep -Fxq 'pkg:alpha' "$OMARCHY_TEST_LOG" ||
+  fail "install-font still installs after quoting a hostile display name"
+pass "install-font does not run extra commands from a quote in the name or family"
+
+bash "$ROOT/bin/omarchy-install-app" "Example App" "alpha; echo PWNED"
+: >"$OMARCHY_TEST_LOG"
+run_presentation >"$test_tmp/app-pkg-inject.out"
+if grep -Fxq 'PWNED' "$test_tmp/app-pkg-inject.out"; then
+  fail "install-app does not run extra commands from a package list" "$(<"$test_tmp/app-pkg-inject.out")"
+fi
+grep -Fxq 'pkg:alpha; echo PWNED' "$OMARCHY_TEST_LOG" ||
+  fail "install-app hands a hostile package list to the package helper as arguments" "$(<"$OMARCHY_TEST_LOG")"
+pass "install-app does not run extra commands from a package list"
+
+bash "$ROOT/bin/omarchy-install-app" "Example App" "$(printf 'alpha\nbeta')"
+: >"$OMARCHY_TEST_LOG"
+run_presentation
+grep -Fxq 'pkg:alpha beta' "$OMARCHY_TEST_LOG" ||
+  fail "install-app keeps every package when the list is newline-separated" "$(<"$OMARCHY_TEST_LOG")"
+pass "install-app keeps every package when the list is newline-separated"
+
+env SHELLOPTS=errexit bash "$ROOT/bin/omarchy-install-app" "Example App" "alpha beta" ||
+  fail "install-app builds its command under an inherited errexit"
+[[ $(<"$OMARCHY_TEST_PRESENTATION") == 'echo Installing\ Example\ App...; omarchy-pkg-add alpha beta' ]] ||
+  fail "install-app builds the same command under an inherited errexit" "$(<"$OMARCHY_TEST_PRESENTATION")"
+env SHELLOPTS=errexit bash "$ROOT/bin/omarchy-install-and-launch" "Example App" "alpha beta" "Disk Usage" ||
+  fail "install-and-launch builds its command under an inherited errexit"
+grep -Fq 'omarchy-pkg-add alpha beta' "$OMARCHY_TEST_PRESENTATION" ||
+  fail "install-and-launch keeps its package list under an inherited errexit" "$(<"$OMARCHY_TEST_PRESENTATION")"
+pass "the installers build their command under an inherited errexit"
+
+bash "$ROOT/bin/omarchy-install-font" "Example Font" "alpha; echo PWNED" "Example Family"
+: >"$OMARCHY_TEST_LOG"
+run_presentation >"$test_tmp/font-pkg-inject.out"
+if grep -Fxq 'PWNED' "$test_tmp/font-pkg-inject.out"; then
+  fail "install-font does not run extra commands from its package" "$(<"$test_tmp/font-pkg-inject.out")"
+fi
+grep -Fxq 'pkg:alpha; echo PWNED' "$OMARCHY_TEST_LOG" ||
+  fail "install-font hands a hostile package to the package helper as one argument" "$(<"$OMARCHY_TEST_LOG")"
+pass "install-font does not run extra commands from its package"
+
+bash "$ROOT/bin/omarchy-install-font" "Example Font" "alpha" "Example Family"
+: >"$OMARCHY_TEST_LOG"
+if OMARCHY_TEST_PKG_STATUS=1 run_presentation; then
+  fail "install-font propagates package installation failure"
+fi
+if grep -q '^font:' "$OMARCHY_TEST_LOG"; then
+  fail "install-font does not set the family after package installation failure" "$(<"$OMARCHY_TEST_LOG")"
+fi
+pass "install-font does not set the family after package installation failure"
+
+bash "$ROOT/bin/omarchy-install-and-launch" "Example App" "alpha; echo PWNED" "Disk Usage"
+: >"$OMARCHY_TEST_LOG"
+run_presentation >"$test_tmp/launch-pkg-inject.out"
+if grep -Fxq 'PWNED' "$test_tmp/launch-pkg-inject.out"; then
+  fail "install-and-launch does not run extra commands from a package list" "$(<"$test_tmp/launch-pkg-inject.out")"
+fi
+grep -Fxq 'pkg:alpha; echo PWNED' "$OMARCHY_TEST_LOG" ||
+  fail "install-and-launch hands a hostile package list to the package helper as arguments" "$(<"$OMARCHY_TEST_LOG")"
+pass "install-and-launch does not run extra commands from a package list"