diff --git a/.github/workflows/sync-setup-script.yml b/.github/workflows/sync-setup-script.yml
new file mode 100644
index 0000000..8aad3fe
--- /dev/null
+++ b/.github/workflows/sync-setup-script.yml
@@ -0,0 +1,32 @@
+name: Sync Setup Script to GitHub Pages
+
+on:
+  push:
+    branches:
+      - main
+    paths:
+      - 'setup.sh'
+  workflow_dispatch:
+
+jobs:
+  sync:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout kagglelink repo
+        uses: actions/checkout@v4
+
+      - name: Create setup file (without .sh extension)
+        run: cp setup.sh setup
+
+      - name: Push setup to GitHub Pages repo
+        uses: dmnemec/copy_file_to_another_repo_action@main
+        env:
+          API_TOKEN_GITHUB: ${{ secrets.PAGES_DEPLOY_TOKEN }}
+        with:
+          source_file: 'setup'
+          destination_repo: 'bhdai/bhdai.github.io'
+          destination_folder: ''
+          destination_branch: 'master'
+          user_email: 'github-actions[bot]@users.noreply.github.com'
+          user_name: 'github-actions[bot]'
+          commit_message: 'Sync setup script from kagglelink repo'
diff --git a/tests/unit/test_argument_parsing.bats b/tests/unit/test_argument_parsing.bats
index 35fc25d..91a7cc1 100644
--- a/tests/unit/test_argument_parsing.bats
+++ b/tests/unit/test_argument_parsing.bats
@@ -88,6 +88,46 @@ teardown() {
     [[ "$output" == *"Usage"* ]] || [[ "$output" == *"-k"* ]] || [[ "$output" == *"help"* ]]
 }
 
+# =============================================================================
+# Exit Code Tests (AC1, AC3)
+# =============================================================================
+
+@test "P0: help flag (-h) should exit with code 0" {
+    run bash setup.sh -h
+    [ "$status" -eq 0 ]
+    [[ "$output" == *"Usage"* ]]
+}
+
+@test "P0: help flag (--help) should exit with code 0" {
+    run bash setup.sh --help
+    [ "$status" -eq 0 ]
+    [[ "$output" == *"Usage"* ]]
+}
+
+@test "P0: unknown option should exit with code 1" {
+    run bash setup.sh --invalid-flag
+    [ "$status" -eq 1 ]
+    [[ "$output" == *"Unknown option"* ]]
+}
+
+@test "P0: missing required arguments should exit with code 1" {
+    run bash setup.sh -k "https://example.com/keys"
+    [ "$status" -eq 1 ]
+}
+
+@test "P0: unknown option should display specific error message" {
+    run bash setup.sh -x value
+    [ "$status" -eq 1 ]
+    [[ "$output" == *"Unknown option: -x"* ]]
+}
+
+@test "P1: usage message should include branch variable" {
+    run bash setup.sh -h
+    [ "$status" -eq 0 ]
+    # Should show branch in usage (via KAGGLELINK_BRANCH variable)
+    [[ "$output" == *"BRANCH"* ]] || [[ "$output" == *"main"* ]]
+}
+
 # =============================================================================
 # URL Validation Tests (Future - when URL validation is implemented)
 # =============================================================================