diff --git a/Makefile b/Makefile
index 2133d13..a98b7ce 100644
--- a/Makefile
+++ b/Makefile
@@ -27,6 +27,9 @@ test-e2e:
 test-e2e-headed:
 	pytest -m "e2e" --browser chromium --headed
 
+test-e2e-headed-slowmo:
+	pytest -m "priority1" --browser chromium --headed --slowmo=2000
+
 test-regression:
 	pytest tests/test_e2e_regression.py -m "regression" --browser chromium
 
diff --git a/tests/conftest.py b/tests/conftest.py
index 89cb6dc..9ca35cc 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -132,6 +132,7 @@ def browser_context_args(browser_context_args):
       **BROWSER_CONFIG,
       "record_video_dir": "test-results/videos/",
       "record_har_path": "test-results/har/trace.har",
+      "record_video_size": {"width": 1280, "height": 720},
   }
 
 
diff --git a/tests/test_e2e_authentication.py b/tests/test_e2e_authentication.py
index 413c13b..fb1be90 100644
--- a/tests/test_e2e_authentication.py
+++ b/tests/test_e2e_authentication.py
@@ -80,7 +80,6 @@ class TestAuthentication:
     submit_button = page.locator("button[type='submit'], input[type='submit']")
     expect(submit_button.first).to_be_visible()
   
-  @pytest.mark.e2e
   def test_page_loads_without_errors(self, app_server, page: Page):
     """Test that the login page loads without console errors"""
     console_errors = []
@@ -121,3 +120,136 @@ class TestAuthentication:
     assert "test_mmt_" in test_database, "Database path should contain test prefix"
     
     print(f"✅ Test database isolation confirmed: {test_database}")
+  
+  # =============================================================================
+  # PRIORITY 1 TESTS - CRITICAL AUTHENTICATION FLOWS
+  # =============================================================================
+  
+  @pytest.mark.e2e
+  @pytest.mark.priority1
+  @pytest.mark.smoke
+  def test_successful_login_with_valid_credentials(self, app_server, test_users, page: Page):
+    """
+    Priority 1 Test: Validate complete successful login flow with valid credentials
+    
+    This test ensures that:
+    1. User can access the login page
+    2. User can enter valid credentials
+    3. Form submission works correctly
+    4. User is redirected to home page after successful authentication
+    5. User session is properly established
+    """
+    admin_user = test_users["admin"]
+    
+    # Step 1: Navigate to login page
+    page.goto(BASE_URL)
+    page.wait_for_load_state("networkidle")
+    
+    # Verify we're on the login page
+    expect(page).to_have_url(f"{BASE_URL}/authlogin/login")
+    
+    # Step 2: Locate form elements
+    email_input = page.locator("input[type='email'], input[name='email']")
+    password_input = page.locator("input[type='password'], input[name='password']")
+    submit_button = page.locator("button[type='submit']")
+    
+    # Verify all required elements are present and visible
+    expect(email_input).to_be_visible()
+    expect(password_input).to_be_visible()
+    expect(submit_button).to_be_visible()
+    
+    # Step 3: Fill in valid credentials
+    email_input.fill(admin_user["email"])
+    password_input.fill(admin_user["password"])
+    
+    # Verify credentials were entered correctly
+    expect(email_input).to_have_value(admin_user["email"])
+    expect(password_input).to_have_value(admin_user["password"])
+    
+    # Step 4: Submit the login form
+    # Use click with wait for navigation to handle the redirect
+    with page.expect_navigation(wait_until="networkidle"):
+      submit_button.click()
+    
+    # DEBUGGING BLOCK - Add this
+    print(f"🔍 Current URL: {page.url}")
+    print(f"🔍 Page title: {page.title()}")
+    
+    # Take screenshot
+    page.screenshot(path="debug_after_login.png")
+    
+    # Save full HTML for inspection
+    with open("debug_page.html", "w", encoding="utf-8") as f:
+      f.write(page.content())
+    
+    # Check specific content that's causing the failure
+    page_content = page.content().lower()
+    login_keywords = ["sign in", "login", "authenticate"]
+    
+    print("🔍 Checking for login keywords:")
+    for keyword in login_keywords:
+      if keyword in page_content:
+        print(f"  ❌ Found '{keyword}' in page content")
+        # Find exactly where this keyword appears
+        occurrences = page.get_by_text(keyword, exact=False)
+        count = occurrences.count()
+        print(f"     Found in {count} elements:")
+        for i in range(min(count, 3)):  # Show first 3 occurrences
+          element = occurrences.nth(i)
+          try:
+            print(f"     - Element {i}: '{element.inner_text()[:50]}...' (visible: {element.is_visible()})")
+          except:
+            print(f"     - Element {i}: Could not get text")
+      else:
+        print(f"  ✅ '{keyword}' NOT found")
+    
+    # Your original assertion (will still fail, but now you have debug info)
+    has_login_content = any(keyword in page_content for keyword in login_keywords)
+    assert not has_login_content, "Login content still visible after successful authentication"
+    
+    page.pause()
+    
+    # Step 5: Verify successful authentication and redirect
+    # Should be redirected to the home page
+    expect(page).to_have_url(BASE_URL + "/")
+    
+    # Step 6: Verify we're actually authenticated (not redirected back to login)
+    # The page should load without being redirected back to login
+    page.wait_for_load_state("networkidle")
+    current_url = page.url
+    assert not current_url.endswith("/authlogin/login"), f"User was redirected back to login page: {current_url}"
+    
+    # Step 7: Verify authenticated content is present
+    # Check that we don't see login-related content anymore
+    page_content = page.content().lower()
+    login_keywords = ["sign in", "login", "authenticate"]
+    
+    # Should not see login form elements on authenticated page
+    has_login_content = any(keyword in page_content for keyword in login_keywords)
+    assert not has_login_content, "Login content still visible after successful authentication"
+    
+    # Step 8: Verify no error messages are displayed
+    # Look for common error message containers
+    error_selectors = [
+        ".error",
+        ".alert-error",
+        ".bg-error",
+        "[class*='error']",
+        ".text-red",
+        "[class*='text-red']"
+    ]
+    
+    for error_selector in error_selectors:
+      error_elements = page.locator(error_selector)
+      if error_elements.count() > 0:
+        # If error elements exist, they should not be visible or should be empty
+        for i in range(error_elements.count()):
+          element = error_elements.nth(i)
+          if element.is_visible():
+            element_text = element.inner_text().strip()
+            assert not element_text, f"Error message found after successful login: {element_text}"
+    
+    # Step 9: Verify the page has expected title
+    expect(page).to_have_title("My Managing Tools")
+    
+    print(f"✅ Successful login test completed - User {admin_user['email']} authenticated successfully")