diff --git a/scripts/patches/cowork.sh b/scripts/patches/cowork.sh
index 35853c0..3a2685f 100644
--- a/scripts/patches/cowork.sh
+++ b/scripts/patches/cowork.sh
@@ -807,12 +807,27 @@ install_node_pty() {
 		echo '{"name":"node-pty-build","version":"1.0.0","private":true}' > package.json
 
 		echo 'Installing node-pty (this compiles native module)...'
-		if npm install node-pty 2>&1; then
-			echo 'node-pty installed successfully'
-			pty_src_dir="$node_pty_build_dir/node_modules/node-pty"
-		else
-			echo 'Failed to install node-pty - terminal features may not work'
+		# Fail loudly on npm install failure rather than warn-and-continue.
+		# The previous behavior silently dropped pty_src_dir, skipped the
+		# entire copy block, and shipped the upstream Windows node-pty
+		# binaries (the #401 failure mode). check_dependencies should now
+		# install gcc/g++/make/python3 before we get here, so this branch
+		# is the last line of defense for build-tool gaps that auto-install
+		# couldn't fix (unknown distro, broken package mirror, etc.).
+		if ! npm install node-pty 2>&1; then
+			echo "Error: 'npm install node-pty' failed." >&2
+			echo 'node-pty has a native module compiled via node-gyp;' >&2
+			echo 'this usually means the build environment lacks a C/C++' >&2
+			echo 'compiler, make, or python3.' >&2
+			echo '' >&2
+			echo 'Install build tools and re-run:' >&2
+			echo '  Debian/Ubuntu: sudo apt install build-essential python3' >&2
+			echo '  Fedora/RHEL:   sudo dnf install gcc gcc-c++ make python3' >&2
+			cd "$project_root" || exit 1
+			exit 1
 		fi
+		echo 'node-pty installed successfully'
+		pty_src_dir="$node_pty_build_dir/node_modules/node-pty"
 	fi
 
 	if [[ -n $pty_src_dir && -d $pty_src_dir ]]; then
diff --git a/scripts/setup/dependencies.sh b/scripts/setup/dependencies.sh
index 3f39425..1b4cff9 100644
--- a/scripts/setup/dependencies.sh
+++ b/scripts/setup/dependencies.sh
@@ -22,32 +22,51 @@ check_dependencies() {
 		rpm) all_deps="$all_deps rpmbuild" ;;
 	esac
 
+	# node-pty has a native C++ module compiled via node-gyp during
+	# `npm install`. Without gcc/g++/make/python3 the install silently
+	# emits a warning, leaves pty_src_dir empty, and the build ends up
+	# shipping the upstream Windows binaries (the #401 failure mode).
+	# Skip when --node-pty-dir is set (Nix and explicit overrides bring
+	# their own pre-built node-pty).
+	if [[ -z ${node_pty_dir:-} ]]; then
+		all_deps="$all_deps gcc g++ make python3"
+	fi
+
 	# Command-to-package mappings per distro family
 	declare -A debian_pkgs=(
 		[p7zip]='p7zip-full' [wget]='wget' [wrestool]='icoutils'
 		[icotool]='icoutils' [convert]='imagemagick'
 		[dpkg-deb]='dpkg-dev' [rpmbuild]='rpm'
+		[gcc]='build-essential' [g++]='build-essential'
+		[make]='build-essential' [python3]='python3'
 	)
 	declare -A rpm_pkgs=(
 		[p7zip]='p7zip p7zip-plugins' [wget]='wget' [wrestool]='icoutils'
 		[icotool]='icoutils' [convert]='ImageMagick'
 		[dpkg-deb]='dpkg' [rpmbuild]='rpm-build'
+		[gcc]='gcc' [g++]='gcc-c++'
+		[make]='make' [python3]='python3'
 	)
 
-	local cmd
+	local cmd pkg
 	for cmd in $all_deps; do
 		if ! check_command "$cmd"; then
 			case "$distro_family" in
-				debian)
-					deps_to_install="$deps_to_install ${debian_pkgs[$cmd]}"
-					;;
-				rpm)
-					deps_to_install="$deps_to_install ${rpm_pkgs[$cmd]}"
-					;;
+				debian) pkg="${debian_pkgs[$cmd]}" ;;
+				rpm)    pkg="${rpm_pkgs[$cmd]}" ;;
 				*)
 					echo "Warning: Cannot auto-install '$cmd' on unknown distro. Please install manually." >&2
+					continue
 					;;
 			esac
+			# Several commands map to the same package (gcc/g++/make
+			# -> build-essential, wrestool/icotool -> icoutils). Skip
+			# if the package is already queued so the log line stays
+			# readable.
+			case " $deps_to_install " in
+				*" $pkg "*) ;;
+				*) deps_to_install="$deps_to_install $pkg" ;;
+			esac
 		fi
 	done