diff --git a/scripts/install.sh b/scripts/install.sh
index 1d42047..8bf8cd0 100644
--- a/scripts/install.sh
+++ b/scripts/install.sh
@@ -2,71 +2,76 @@
 set -euo pipefail
 
 dry_run=false
-for argument in "$@"; do
-  [ "$argument" != "--dry-run" ] || dry_run=true
+client=""
+platform=""
+update_plugins=false
+while [ $# -gt 0 ]; do
+  case "$1" in
+    --dry-run) dry_run=true; shift ;;
+    --update-plugins) update_plugins=true; shift ;;
+    --client) client=${2:?--client requires a value}; shift 2 ;;
+    --platform) platform=${2:?--platform requires a value}; shift 2 ;;
+    *) printf 'Unknown argument: %s\n' "$1" >&2; exit 1 ;;
+  esac
 done
+
 root=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")/.." && pwd)
 . "$root/scripts/lib/plugins.sh"
+. "$root/scripts/lib/manifest.sh"
 bash "$root/scripts/build.sh"
 generated="$root/generated"
 [ -d "$generated" ] || { printf 'Generated output is missing after a successful build.\n' >&2; exit 1; }
 
-printf 'Select target platform:\n1) Windows\n2) Linux\n'
-while :; do
-  read -r -p 'Selection [1-2] ' platform_selection
-  case "$platform_selection" in 1) platform=windows; break;; 2) platform=linux; break;; esac
-done
-printf 'Select installation target:\n1) Codex\n2) Claude\n3) Both\n'
-while :; do
-  read -r -p 'Selection [1-3] ' selection
-  case "$selection" in 1|2|3) break;; esac
-done
+if [ -z "$platform" ]; then
+  printf 'Select target platform:\n1) Windows\n2) Linux\n'
+  while :; do
+    read -r -p 'Selection [1-2] ' platform_selection
+    case "$platform_selection" in 1) platform=windows; break;; 2) platform=linux; break;; esac
+  done
+else
+  case "$platform" in
+    windows|Windows) platform=windows ;;
+    linux|Linux) platform=linux ;;
+    *) printf 'Unknown --platform value: %s (expected windows or linux)\n' "$platform" >&2; exit 1 ;;
+  esac
+fi
+
+if [ -z "$client" ]; then
+  printf 'Select installation target:\n1) Codex\n2) Claude\n3) Both\n'
+  while :; do
+    read -r -p 'Selection [1-3] ' selection
+    case "$selection" in 1) client=codex; break;; 2) client=claude; break;; 3) client=both; break;; esac
+  done
+else
+  case "$client" in
+    codex|Codex) client=codex ;;
+    claude|Claude) client=claude ;;
+    both|Both) client=both ;;
+    *) printf 'Unknown --client value: %s (expected codex, claude, or both)\n' "$client" >&2; exit 1 ;;
+  esac
+fi
 
 stamp=$(date +%Y%m%d-%H%M%S)
 home_path=${HOME:?HOME is required}
+shell_command=bash
+windows_shell_command='powershell -NoProfile -ExecutionPolicy Bypass -File'
+
 targets=()
-case "$selection" in
-  1|3) targets+=("$generated/codex-$platform|$home_path/.codex" "$generated/codex-$platform/skills|$home_path/.agents/skills");;
+case "$client" in
+  codex|both) targets+=("$generated/codex-$platform|$home_path/.codex" "$generated/codex-$platform/skills|$home_path/.agents/skills");;
 esac
-case "$selection" in
-  2|3) targets+=("$generated/claude-$platform|$home_path/.claude");;
+case "$client" in
+  claude|both) targets+=("$generated/claude-$platform|$home_path/.claude");;
 esac
 
 for target_pair in "${targets[@]}"; do
   source=${target_pair%%|*}
   destination=${target_pair#*|}
-  while IFS= read -r -d '' source_file; do
-    relative=${source_file#"$source/"}
-    target="$destination/$relative"
-    if "$dry_run"; then printf 'DRYRUN %s -> %s\n' "$source_file" "$target"; continue; fi
-    if [ -f "$target" ]; then
-      backup="$destination/backups/$relative.$stamp"
-      mkdir -p "$(dirname -- "$backup")"
-      cp "$target" "$backup"
-    fi
-    mkdir -p "$(dirname -- "$target")"
-    content=$(<"$source_file")
-    if [[ "$content" == *'__AI_CONFIG_ROOT__'* || "$content" == *'__HOOK_COMMAND__'* || "$content" == *'__WINDOWS_HOOK_COMMAND__'* ]]; then
-      replacement=$destination
-      if command -v cygpath >/dev/null; then replacement=$(cygpath -m "$destination"); fi
-      content=${content//__AI_CONFIG_ROOT__/$replacement}
-      content=${content//__HOOK_COMMAND__/bash}
-      content=${content//__WINDOWS_HOOK_COMMAND__/bash}
-      content=${content//__HOOK_SCRIPT__/flashbang.sh}
-      content=${content//__WINDOWS_HOOK_SCRIPT__/flashbang.sh}
-      printf '%s' "$content" > "$target"
-    else
-      cp "$source_file" "$target"
-    fi
-    printf 'INSTALL %s\n' "$target"
-  done < <(find "$source" -type f -print0)
+  ai_config_root=$destination
+  command -v cygpath >/dev/null && ai_config_root=$(cygpath -m "$destination")
+  sync_managed_destination "$source" "$destination" "$stamp" "$ai_config_root" "$shell_command" "$windows_shell_command" "$dry_run"
 done
 
-client_selection=both
-case "$selection" in
-  1) client_selection=codex;;
-  2) client_selection=claude;;
-esac
-install_configured_plugins "$root" "$client_selection" "$dry_run" true
+install_configured_plugins "$root" "$client" "$dry_run" "$update_plugins"
 
 if "$dry_run"; then printf 'PASS install dry-run\n'; else printf 'PASS install\n'; fi