diff --git a/.architecture-rules/module.yaml b/.architecture-rules/module.yaml
index 6e418fe9..e617330b 100644
--- a/.architecture-rules/module.yaml
+++ b/.architecture-rules/module.yaml
@@ -551,3 +551,175 @@ module_rules:
         - "__init__.py"
         - "base.py"
         - "auth.py"
+
+  # =========================================================================
+  # Module Definition Completeness Rules
+  # =========================================================================
+
+  - id: "MOD-020"
+    name: "Module definition must have required attributes"
+    severity: "warning"
+    description: |
+      Module definitions should include at minimum:
+      - code: Module identifier
+      - name: Human-readable name
+      - description: What the module does
+      - version: Semantic version
+      - features: List of features (unless infrastructure module)
+      - permissions: Access control definitions (unless internal or storefront-only)
+
+      EXAMPLES (incomplete):
+        module = ModuleDefinition(
+            code="cart",
+            name="Shopping Cart",
+            description="...",
+            version="1.0.0",
+            # Missing features and permissions
+        )
+
+      EXAMPLES (complete):
+        module = ModuleDefinition(
+            code="orders",
+            name="Order Management",
+            description="...",
+            version="1.0.0",
+            features=["order_management", "fulfillment_tracking"],
+            permissions=[
+                PermissionDefinition(id="orders.view", ...),
+            ],
+        )
+
+      EXCEPTIONS:
+        - is_internal=True modules may skip permissions
+        - Infrastructure modules (is_core=True with no UI) may skip features
+        - Storefront-only modules (session-based, no admin UI) may have minimal permissions
+
+      WHY THIS MATTERS:
+      - Consistency: All modules follow the same definition pattern
+      - RBAC: Permissions enable proper role-based access control
+      - Feature flags: Features enable selective module functionality
+    pattern:
+      file_pattern: "app/modules/*/definition.py"
+      required_attributes:
+        - "code"
+        - "name"
+        - "description"
+        - "version"
+
+  - id: "MOD-021"
+    name: "Modules with menus should have features"
+    severity: "warning"
+    description: |
+      If a module defines menu items or menu sections, it should also
+      define features to describe what functionality it provides.
+
+      Menus indicate the module has UI and user-facing functionality,
+      which should be documented as features.
+
+      WRONG:
+        module = ModuleDefinition(
+            code="billing",
+            menus={
+                FrontendType.ADMIN: [...],
+            },
+            # Missing features list
+        )
+
+      RIGHT:
+        module = ModuleDefinition(
+            code="billing",
+            features=[
+                "subscription_management",
+                "billing_history",
+                "invoice_generation",
+            ],
+            menus={
+                FrontendType.ADMIN: [...],
+            },
+        )
+
+      WHY THIS MATTERS:
+      - Documentation: Features describe what the module does
+      - Feature flags: Enables/disables specific functionality
+      - Consistency: All UI modules describe their capabilities
+    pattern:
+      file_pattern: "app/modules/*/definition.py"
+      validates:
+        - "menus -> features"
+
+  - id: "MOD-022"
+    name: "Feature modules should have permissions"
+    severity: "info"
+    description: |
+      Modules with features should define permissions unless:
+      - is_internal=True (internal tools like dev_tools)
+      - Storefront-only module (session-based, no authentication)
+
+      Permissions enable role-based access control (RBAC) for module
+      functionality.
+
+      EXCEPTIONS:
+        - is_internal=True modules (internal tooling)
+        - Modules with only storefront features (cart, checkout without admin UI)
+        - Infrastructure modules (contracts, core utilities)
+
+      EXAMPLE:
+        module = ModuleDefinition(
+            code="billing",
+            features=["subscription_management", ...],
+            permissions=[
+                PermissionDefinition(
+                    id="billing.view_subscriptions",
+                    label_key="billing.permissions.view_subscriptions",
+                    description_key="billing.permissions.view_subscriptions_desc",
+                    category="billing",
+                ),
+            ],
+        )
+
+      WHY THIS MATTERS:
+      - RBAC: Permissions enable proper access control
+      - Security: Restrict who can access module features
+      - Consistency: All feature modules define their access rules
+    pattern:
+      file_pattern: "app/modules/*/definition.py"
+      validates:
+        - "features -> permissions"
+      exceptions:
+        - "is_internal=True"
+
+  - id: "MOD-023"
+    name: "Modules with routers should use get_*_with_routers pattern"
+    severity: "info"
+    description: |
+      Modules that define routers (admin_router, vendor_router, etc.)
+      should follow the lazy import pattern with a dedicated function:
+
+        def get_{module}_module_with_routers() -> ModuleDefinition:
+
+      This pattern:
+      1. Avoids circular imports during module initialization
+      2. Ensures routers are attached at the right time
+      3. Provides a consistent API for router registration
+
+      WRONG:
+        # Direct router assignment at module level
+        module.admin_router = admin_router
+
+      RIGHT:
+        def _get_admin_router():
+            from app.modules.orders.routes.admin import admin_router
+            return admin_router
+
+        def get_orders_module_with_routers() -> ModuleDefinition:
+            orders_module.admin_router = _get_admin_router()
+            return orders_module
+
+      WHY THIS MATTERS:
+      - Prevents circular imports
+      - Consistent pattern across all modules
+      - Clear API for module registration
+    pattern:
+      file_pattern: "app/modules/*/definition.py"
+      validates:
+        - "router imports -> get_*_with_routers function"
diff --git a/app/api/v1/public/__init__.py b/app/api/v1/platform/__init__.py
similarity index 100%
rename from app/api/v1/public/__init__.py
rename to app/api/v1/platform/__init__.py
diff --git a/app/api/v1/public/signup.py b/app/api/v1/platform/signup.py
similarity index 100%
rename from app/api/v1/public/signup.py
rename to app/api/v1/platform/signup.py
diff --git a/app/modules/analytics/definition.py b/app/modules/analytics/definition.py
index 3f2cd10c..e7241e90 100644
--- a/app/modules/analytics/definition.py
+++ b/app/modules/analytics/definition.py
@@ -6,7 +6,7 @@ Defines the analytics module including its features, menu items,
 route configurations, and self-contained module settings.
 """
 
-from app.modules.base import MenuItemDefinition, MenuSectionDefinition, ModuleDefinition
+from app.modules.base import MenuItemDefinition, MenuSectionDefinition, ModuleDefinition, PermissionDefinition
 from app.modules.enums import FrontendType
 
 
@@ -37,6 +37,27 @@ analytics_module = ModuleDefinition(
         "export_reports",  # Export to CSV/Excel
         "usage_metrics",  # Usage and performance metrics
     ],
+    # Module-driven permissions
+    permissions=[
+        PermissionDefinition(
+            id="analytics.view",
+            label_key="analytics.permissions.view",
+            description_key="analytics.permissions.view_desc",
+            category="analytics",
+        ),
+        PermissionDefinition(
+            id="analytics.export",
+            label_key="analytics.permissions.export",
+            description_key="analytics.permissions.export_desc",
+            category="analytics",
+        ),
+        PermissionDefinition(
+            id="analytics.manage_dashboards",
+            label_key="analytics.permissions.manage_dashboards",
+            description_key="analytics.permissions.manage_dashboards_desc",
+            category="analytics",
+        ),
+    ],
     menu_items={
         FrontendType.ADMIN: [
             # Analytics appears in dashboard for admin
diff --git a/app/modules/billing/definition.py b/app/modules/billing/definition.py
index bd4c09de..48df80f9 100644
--- a/app/modules/billing/definition.py
+++ b/app/modules/billing/definition.py
@@ -6,7 +6,7 @@ Defines the billing module including its features, menu items,
 route configurations, and scheduled tasks.
 """
 
-from app.modules.base import MenuItemDefinition, MenuSectionDefinition, ModuleDefinition, ScheduledTask
+from app.modules.base import MenuItemDefinition, MenuSectionDefinition, ModuleDefinition, PermissionDefinition, ScheduledTask
 from app.modules.enums import FrontendType
 
 
@@ -42,6 +42,39 @@ billing_module = ModuleDefinition(
         "trial_management",  # Manage vendor trial periods
         "limit_overrides",  # Override tier limits per vendor
     ],
+    # Module-driven permissions
+    permissions=[
+        PermissionDefinition(
+            id="billing.view_tiers",
+            label_key="billing.permissions.view_tiers",
+            description_key="billing.permissions.view_tiers_desc",
+            category="billing",
+        ),
+        PermissionDefinition(
+            id="billing.manage_tiers",
+            label_key="billing.permissions.manage_tiers",
+            description_key="billing.permissions.manage_tiers_desc",
+            category="billing",
+        ),
+        PermissionDefinition(
+            id="billing.view_subscriptions",
+            label_key="billing.permissions.view_subscriptions",
+            description_key="billing.permissions.view_subscriptions_desc",
+            category="billing",
+        ),
+        PermissionDefinition(
+            id="billing.manage_subscriptions",
+            label_key="billing.permissions.manage_subscriptions",
+            description_key="billing.permissions.manage_subscriptions_desc",
+            category="billing",
+        ),
+        PermissionDefinition(
+            id="billing.view_invoices",
+            label_key="billing.permissions.view_invoices",
+            description_key="billing.permissions.view_invoices_desc",
+            category="billing",
+        ),
+    ],
     menu_items={
         FrontendType.ADMIN: [
             "subscription-tiers",  # Manage tier definitions
diff --git a/app/modules/billing/routes/api/public.py b/app/modules/billing/routes/api/platform.py
similarity index 100%
rename from app/modules/billing/routes/api/public.py
rename to app/modules/billing/routes/api/platform.py
diff --git a/app/modules/billing/routes/pages/public.py b/app/modules/billing/routes/pages/platform.py
similarity index 100%
rename from app/modules/billing/routes/pages/public.py
rename to app/modules/billing/routes/pages/platform.py
diff --git a/app/modules/billing/templates/billing/public/pricing.html b/app/modules/billing/templates/billing/platform/pricing.html
similarity index 100%
rename from app/modules/billing/templates/billing/public/pricing.html
rename to app/modules/billing/templates/billing/platform/pricing.html
diff --git a/app/modules/billing/templates/billing/public/signup-success.html b/app/modules/billing/templates/billing/platform/signup-success.html
similarity index 100%
rename from app/modules/billing/templates/billing/public/signup-success.html
rename to app/modules/billing/templates/billing/platform/signup-success.html
diff --git a/app/modules/billing/templates/billing/public/signup.html b/app/modules/billing/templates/billing/platform/signup.html
similarity index 100%
rename from app/modules/billing/templates/billing/public/signup.html
rename to app/modules/billing/templates/billing/platform/signup.html
diff --git a/app/modules/cart/definition.py b/app/modules/cart/definition.py
index 7bb2a966..2e0a347c 100644
--- a/app/modules/cart/definition.py
+++ b/app/modules/cart/definition.py
@@ -6,7 +6,8 @@ This module provides shopping cart functionality for customer storefronts.
 It is session-based and does not require customer authentication.
 """
 
-from app.modules.base import ModuleDefinition
+from app.modules.base import ModuleDefinition, PermissionDefinition
+
 
 module = ModuleDefinition(
     code="cart",
@@ -15,4 +16,29 @@ module = ModuleDefinition(
     version="1.0.0",
     is_self_contained=True,
     requires=["inventory"],  # Checks inventory availability
+    features=[
+        "cart_management",  # Basic cart CRUD operations
+        "cart_persistence",  # Session and database persistence
+        "cart_item_operations",  # Add, update, remove items
+        "shipping_calculation",  # Calculate shipping for cart
+        "promotion_application",  # Apply discounts and promotions
+    ],
+    # Note: Cart is primarily session-based storefront functionality.
+    # These permissions are for admin access to cart data/settings.
+    permissions=[
+        PermissionDefinition(
+            id="cart.view",
+            label_key="cart.permissions.view",
+            description_key="cart.permissions.view_desc",
+            category="cart",
+        ),
+        PermissionDefinition(
+            id="cart.manage",
+            label_key="cart.permissions.manage",
+            description_key="cart.permissions.manage_desc",
+            category="cart",
+        ),
+    ],
+    # Cart is storefront-only - no admin/vendor menus needed
+    menu_items={},
 )
diff --git a/app/modules/catalog/definition.py b/app/modules/catalog/definition.py
index ba672021..009ea55e 100644
--- a/app/modules/catalog/definition.py
+++ b/app/modules/catalog/definition.py
@@ -16,6 +16,14 @@ module = ModuleDefinition(
     version="1.0.0",
     is_self_contained=True,
     requires=["inventory"],
+    features=[
+        "product_catalog",  # Core product catalog functionality
+        "product_search",  # Search and filtering
+        "product_variants",  # Product variants management
+        "product_categories",  # Category organization
+        "product_attributes",  # Custom attributes
+        "product_import_export",  # Bulk import/export
+    ],
     # Module-driven permissions
     permissions=[
         PermissionDefinition(
diff --git a/app/modules/checkout/definition.py b/app/modules/checkout/definition.py
index 127c16b9..50c719fd 100644
--- a/app/modules/checkout/definition.py
+++ b/app/modules/checkout/definition.py
@@ -1,7 +1,13 @@
 # app/modules/checkout/definition.py
-"""Checkout module definition."""
+"""
+Checkout module definition.
+
+This module handles the checkout flow, converting cart contents into orders.
+Orchestrates payment processing and order creation.
+"""
+
+from app.modules.base import ModuleDefinition, PermissionDefinition
 
-from app.modules.base import ModuleDefinition
 
 module = ModuleDefinition(
     code="checkout",
@@ -10,4 +16,29 @@ module = ModuleDefinition(
     version="1.0.0",
     is_self_contained=True,
     requires=["cart", "orders", "payments", "customers"],
+    features=[
+        "checkout_flow",  # Multi-step checkout process
+        "order_creation",  # Create orders from cart
+        "payment_processing",  # Payment integration during checkout
+        "checkout_validation",  # Address, inventory, payment validation
+        "guest_checkout",  # Allow checkout without account
+    ],
+    # Note: Checkout is primarily storefront functionality.
+    # These permissions are for admin access to checkout settings.
+    permissions=[
+        PermissionDefinition(
+            id="checkout.view_settings",
+            label_key="checkout.permissions.view_settings",
+            description_key="checkout.permissions.view_settings_desc",
+            category="checkout",
+        ),
+        PermissionDefinition(
+            id="checkout.manage_settings",
+            label_key="checkout.permissions.manage_settings",
+            description_key="checkout.permissions.manage_settings_desc",
+            category="checkout",
+        ),
+    ],
+    # Checkout is storefront-only - no admin/vendor menus needed
+    menu_items={},
 )
diff --git a/app/modules/cms/definition.py b/app/modules/cms/definition.py
index 343cc735..50e94e84 100644
--- a/app/modules/cms/definition.py
+++ b/app/modules/cms/definition.py
@@ -12,7 +12,7 @@ This is a self-contained module with:
 - Templates: app.modules.cms.templates (namespaced as cms/)
 """
 
-from app.modules.base import MenuItemDefinition, MenuSectionDefinition, ModuleDefinition
+from app.modules.base import MenuItemDefinition, MenuSectionDefinition, ModuleDefinition, PermissionDefinition
 from app.modules.enums import FrontendType
 
 
@@ -35,6 +35,7 @@ cms_module = ModuleDefinition(
     code="cms",
     name="Content Management",
     description="Content pages, media library, and vendor themes.",
+    version="1.0.0",
     features=[
         "cms_basic",  # Basic page editing
         "cms_custom_pages",  # Custom page creation
@@ -43,6 +44,39 @@ cms_module = ModuleDefinition(
         "cms_seo",  # SEO tools
         "media_library",  # Media file management
     ],
+    # Module-driven permissions
+    permissions=[
+        PermissionDefinition(
+            id="cms.view_pages",
+            label_key="cms.permissions.view_pages",
+            description_key="cms.permissions.view_pages_desc",
+            category="cms",
+        ),
+        PermissionDefinition(
+            id="cms.manage_pages",
+            label_key="cms.permissions.manage_pages",
+            description_key="cms.permissions.manage_pages_desc",
+            category="cms",
+        ),
+        PermissionDefinition(
+            id="cms.view_media",
+            label_key="cms.permissions.view_media",
+            description_key="cms.permissions.view_media_desc",
+            category="cms",
+        ),
+        PermissionDefinition(
+            id="cms.manage_media",
+            label_key="cms.permissions.manage_media",
+            description_key="cms.permissions.manage_media_desc",
+            category="cms",
+        ),
+        PermissionDefinition(
+            id="cms.manage_themes",
+            label_key="cms.permissions.manage_themes",
+            description_key="cms.permissions.manage_themes_desc",
+            category="cms",
+        ),
+    ],
     menu_items={
         FrontendType.ADMIN: [
             "content-pages",  # Platform content pages
diff --git a/app/modules/cms/routes/pages/public.py b/app/modules/cms/routes/pages/platform.py
similarity index 100%
rename from app/modules/cms/routes/pages/public.py
rename to app/modules/cms/routes/pages/platform.py
diff --git a/app/modules/cms/templates/cms/public/content-page.html b/app/modules/cms/templates/cms/platform/content-page.html
similarity index 100%
rename from app/modules/cms/templates/cms/public/content-page.html
rename to app/modules/cms/templates/cms/platform/content-page.html
diff --git a/app/modules/cms/templates/cms/public/homepage-default.html b/app/modules/cms/templates/cms/platform/homepage-default.html
similarity index 100%
rename from app/modules/cms/templates/cms/public/homepage-default.html
rename to app/modules/cms/templates/cms/platform/homepage-default.html
diff --git a/app/modules/cms/templates/cms/public/homepage-minimal.html b/app/modules/cms/templates/cms/platform/homepage-minimal.html
similarity index 100%
rename from app/modules/cms/templates/cms/public/homepage-minimal.html
rename to app/modules/cms/templates/cms/platform/homepage-minimal.html
diff --git a/app/modules/cms/templates/cms/public/homepage-modern.html b/app/modules/cms/templates/cms/platform/homepage-modern.html
similarity index 100%
rename from app/modules/cms/templates/cms/public/homepage-modern.html
rename to app/modules/cms/templates/cms/platform/homepage-modern.html
diff --git a/app/modules/cms/templates/cms/public/homepage-wizamart.html b/app/modules/cms/templates/cms/platform/homepage-wizamart.html
similarity index 100%
rename from app/modules/cms/templates/cms/public/homepage-wizamart.html
rename to app/modules/cms/templates/cms/platform/homepage-wizamart.html
diff --git a/app/modules/cms/templates/cms/public/sections/_cta.html b/app/modules/cms/templates/cms/platform/sections/_cta.html
similarity index 100%
rename from app/modules/cms/templates/cms/public/sections/_cta.html
rename to app/modules/cms/templates/cms/platform/sections/_cta.html
diff --git a/app/modules/cms/templates/cms/public/sections/_features.html b/app/modules/cms/templates/cms/platform/sections/_features.html
similarity index 100%
rename from app/modules/cms/templates/cms/public/sections/_features.html
rename to app/modules/cms/templates/cms/platform/sections/_features.html
diff --git a/app/modules/cms/templates/cms/public/sections/_hero.html b/app/modules/cms/templates/cms/platform/sections/_hero.html
similarity index 100%
rename from app/modules/cms/templates/cms/public/sections/_hero.html
rename to app/modules/cms/templates/cms/platform/sections/_hero.html
diff --git a/app/modules/cms/templates/cms/public/sections/_pricing.html b/app/modules/cms/templates/cms/platform/sections/_pricing.html
similarity index 100%
rename from app/modules/cms/templates/cms/public/sections/_pricing.html
rename to app/modules/cms/templates/cms/platform/sections/_pricing.html
diff --git a/app/modules/core/routes/api/public.py b/app/modules/core/routes/api/platform.py
similarity index 100%
rename from app/modules/core/routes/api/public.py
rename to app/modules/core/routes/api/platform.py
diff --git a/app/modules/dev_tools/definition.py b/app/modules/dev_tools/definition.py
index 08de8680..3884363c 100644
--- a/app/modules/dev_tools/definition.py
+++ b/app/modules/dev_tools/definition.py
@@ -85,20 +85,8 @@ dev_tools_module = ModuleDefinition(
     schemas_path="app.modules.dev_tools.schemas",
     exceptions_path="app.modules.dev_tools.exceptions",
     tasks_path="app.modules.dev_tools.tasks",
-    # =========================================================================
-    # Scheduled Tasks
-    # =========================================================================
     # Note: Code quality and test tasks are on-demand, not scheduled.
-    # If scheduled scans are desired, they can be added here:
-    # scheduled_tasks=[
-    #     ScheduledTask(
-    #         name="dev_tools.nightly_code_scan",
-    #         task="app.modules.dev_tools.tasks.code_quality.execute_code_quality_scan",
-    #         schedule="0 2 * * *",  # Daily at 02:00
-    #         options={"queue": "long_running"},
-    #     ),
-    # ],
-    scheduled_tasks=[],
+    # If scheduled scans are desired, add ScheduledTask entries here.
 )
 
 
diff --git a/app/modules/loyalty/definition.py b/app/modules/loyalty/definition.py
index 85f9de2c..423c8976 100644
--- a/app/modules/loyalty/definition.py
+++ b/app/modules/loyalty/definition.py
@@ -6,7 +6,7 @@ Defines the loyalty module including its features, menu items,
 route configurations, and scheduled tasks.
 """
 
-from app.modules.base import MenuItemDefinition, MenuSectionDefinition, ModuleDefinition, ScheduledTask
+from app.modules.base import MenuItemDefinition, MenuSectionDefinition, ModuleDefinition, PermissionDefinition, ScheduledTask
 from app.modules.enums import FrontendType
 
 
@@ -24,11 +24,11 @@ def _get_vendor_router():
     return vendor_router
 
 
-def _get_public_router():
-    """Lazy import of public router to avoid circular imports."""
-    from app.modules.loyalty.routes.api.public import public_router
+def _get_platform_router():
+    """Lazy import of platform router to avoid circular imports."""
+    from app.modules.loyalty.routes.api.platform import platform_router
 
-    return public_router
+    return platform_router
 
 
 # Loyalty module definition
@@ -60,6 +60,33 @@ loyalty_module = ModuleDefinition(
         "loyalty_stats",  # Dashboard statistics
         "loyalty_reports",  # Transaction reports
     ],
+    # Module-driven permissions
+    permissions=[
+        PermissionDefinition(
+            id="loyalty.view_programs",
+            label_key="loyalty.permissions.view_programs",
+            description_key="loyalty.permissions.view_programs_desc",
+            category="loyalty",
+        ),
+        PermissionDefinition(
+            id="loyalty.manage_programs",
+            label_key="loyalty.permissions.manage_programs",
+            description_key="loyalty.permissions.manage_programs_desc",
+            category="loyalty",
+        ),
+        PermissionDefinition(
+            id="loyalty.view_rewards",
+            label_key="loyalty.permissions.view_rewards",
+            description_key="loyalty.permissions.view_rewards_desc",
+            category="loyalty",
+        ),
+        PermissionDefinition(
+            id="loyalty.manage_rewards",
+            label_key="loyalty.permissions.manage_rewards",
+            description_key="loyalty.permissions.manage_rewards_desc",
+            category="loyalty",
+        ),
+    ],
     menu_items={
         FrontendType.ADMIN: [
             "loyalty-programs",  # View all programs
@@ -168,8 +195,7 @@ def get_loyalty_module_with_routers() -> ModuleDefinition:
     """
     loyalty_module.admin_router = _get_admin_router()
     loyalty_module.vendor_router = _get_vendor_router()
-    # Note: public_router needs to be attached separately in main.py
-    # as it doesn't require authentication
+    loyalty_module.platform_router = _get_platform_router()
     return loyalty_module
 
 
diff --git a/app/modules/loyalty/routes/api/public.py b/app/modules/loyalty/routes/api/platform.py
similarity index 100%
rename from app/modules/loyalty/routes/api/public.py
rename to app/modules/loyalty/routes/api/platform.py
diff --git a/app/modules/marketplace/definition.py b/app/modules/marketplace/definition.py
index 78f7d6ad..5e3a5c6c 100644
--- a/app/modules/marketplace/definition.py
+++ b/app/modules/marketplace/definition.py
@@ -8,7 +8,7 @@ dependencies, route configurations, and scheduled tasks.
 Note: This module requires the inventory module to be enabled.
 """
 
-from app.modules.base import MenuItemDefinition, MenuSectionDefinition, ModuleDefinition, ScheduledTask
+from app.modules.base import MenuItemDefinition, MenuSectionDefinition, ModuleDefinition, PermissionDefinition, ScheduledTask
 from app.modules.enums import FrontendType
 
 
@@ -43,6 +43,27 @@ marketplace_module = ModuleDefinition(
         "order_import",  # Import orders from marketplace
         "marketplace_analytics",  # Marketplace performance metrics
     ],
+    # Module-driven permissions
+    permissions=[
+        PermissionDefinition(
+            id="marketplace.view_integration",
+            label_key="marketplace.permissions.view_integration",
+            description_key="marketplace.permissions.view_integration_desc",
+            category="marketplace",
+        ),
+        PermissionDefinition(
+            id="marketplace.manage_integration",
+            label_key="marketplace.permissions.manage_integration",
+            description_key="marketplace.permissions.manage_integration_desc",
+            category="marketplace",
+        ),
+        PermissionDefinition(
+            id="marketplace.sync_products",
+            label_key="marketplace.permissions.sync_products",
+            description_key="marketplace.permissions.sync_products_desc",
+            category="marketplace",
+        ),
+    ],
     menu_items={
         FrontendType.ADMIN: [
             "marketplace-letzshop",  # Marketplace monitoring
diff --git a/app/modules/marketplace/routes/api/public.py b/app/modules/marketplace/routes/api/platform.py
similarity index 100%
rename from app/modules/marketplace/routes/api/public.py
rename to app/modules/marketplace/routes/api/platform.py
diff --git a/app/modules/marketplace/routes/pages/public.py b/app/modules/marketplace/routes/pages/platform.py
similarity index 100%
rename from app/modules/marketplace/routes/pages/public.py
rename to app/modules/marketplace/routes/pages/platform.py
diff --git a/app/modules/marketplace/templates/marketplace/public/find-shop.html b/app/modules/marketplace/templates/marketplace/platform/find-shop.html
similarity index 100%
rename from app/modules/marketplace/templates/marketplace/public/find-shop.html
rename to app/modules/marketplace/templates/marketplace/platform/find-shop.html
diff --git a/app/modules/messaging/definition.py b/app/modules/messaging/definition.py
index 75f04bac..2e03ba9c 100644
--- a/app/modules/messaging/definition.py
+++ b/app/modules/messaging/definition.py
@@ -6,7 +6,7 @@ Defines the messaging module including its features, menu items,
 route configurations, and self-contained module settings.
 """
 
-from app.modules.base import MenuItemDefinition, MenuSectionDefinition, ModuleDefinition
+from app.modules.base import MenuItemDefinition, MenuSectionDefinition, ModuleDefinition, PermissionDefinition
 from app.modules.enums import FrontendType
 
 
@@ -37,6 +37,27 @@ messaging_module = ModuleDefinition(
         "message_attachments",  # File attachments
         "admin_notifications",  # System admin notifications
     ],
+    # Module-driven permissions
+    permissions=[
+        PermissionDefinition(
+            id="messaging.view_messages",
+            label_key="messaging.permissions.view_messages",
+            description_key="messaging.permissions.view_messages_desc",
+            category="messaging",
+        ),
+        PermissionDefinition(
+            id="messaging.send_messages",
+            label_key="messaging.permissions.send_messages",
+            description_key="messaging.permissions.send_messages_desc",
+            category="messaging",
+        ),
+        PermissionDefinition(
+            id="messaging.manage_templates",
+            label_key="messaging.permissions.manage_templates",
+            description_key="messaging.permissions.manage_templates_desc",
+            category="messaging",
+        ),
+    ],
     menu_items={
         FrontendType.ADMIN: [
             "messages",  # Admin messages
diff --git a/app/modules/payments/definition.py b/app/modules/payments/definition.py
index 73fd2e43..ce1305b8 100644
--- a/app/modules/payments/definition.py
+++ b/app/modules/payments/definition.py
@@ -15,7 +15,7 @@ This separation allows:
 3. Orders without billing (customer payments only)
 """
 
-from app.modules.base import ModuleDefinition
+from app.modules.base import ModuleDefinition, PermissionDefinition
 from app.modules.enums import FrontendType
 
 
@@ -51,6 +51,27 @@ payments_module = ModuleDefinition(
         "bank_transfer",  # Bank transfer support
         "transaction_history",  # Transaction records
     ],
+    # Module-driven permissions
+    permissions=[
+        PermissionDefinition(
+            id="payments.view_gateways",
+            label_key="payments.permissions.view_gateways",
+            description_key="payments.permissions.view_gateways_desc",
+            category="payments",
+        ),
+        PermissionDefinition(
+            id="payments.manage_gateways",
+            label_key="payments.permissions.manage_gateways",
+            description_key="payments.permissions.manage_gateways_desc",
+            category="payments",
+        ),
+        PermissionDefinition(
+            id="payments.view_transactions",
+            label_key="payments.permissions.view_transactions",
+            description_key="payments.permissions.view_transactions_desc",
+            category="payments",
+        ),
+    ],
     menu_items={
         FrontendType.ADMIN: [
             "payment-gateways",  # Configure payment gateways
@@ -61,7 +82,14 @@ payments_module = ModuleDefinition(
     },
     is_core=False,
     is_internal=False,
-    is_self_contained=True,  # Enable auto-discovery from routes/api/
+    # =========================================================================
+    # Self-Contained Module Configuration
+    # =========================================================================
+    is_self_contained=True,
+    services_path="app.modules.payments.services",
+    models_path="app.modules.payments.models",
+    schemas_path="app.modules.payments.schemas",
+    exceptions_path="app.modules.payments.exceptions",
 )
 
 
diff --git a/app/templates/public/base.html b/app/templates/platform/base.html
similarity index 100%
rename from app/templates/public/base.html
rename to app/templates/platform/base.html
diff --git a/docs/architecture/module-system.md b/docs/architecture/module-system.md
index 70a69114..dcc8aba8 100644
--- a/docs/architecture/module-system.md
+++ b/docs/architecture/module-system.md
@@ -72,33 +72,35 @@ touch app/modules/mymodule/exceptions.py
 
 ## Three-Tier Classification
 
-### Core Modules (4)
+### Core Modules (5)
 
 Core modules are **always enabled** and cannot be disabled. They provide fundamental platform functionality.
 
-| Module | Description | Key Features |
-|--------|-------------|--------------|
-| `core` | Dashboard, settings, profile | Basic platform operation |
-| `tenancy` | Platform, company, vendor, admin user management | Multi-tenant infrastructure |
-| `cms` | Content pages, media library, themes | Content management |
-| `customers` | Customer database, profiles, segmentation | Customer data management |
+| Module | Description | Key Features | Permissions |
+|--------|-------------|--------------|-------------|
+| `contracts` | Cross-module protocols and interfaces | Service protocols, type-safe interfaces | - |
+| `core` | Dashboard, settings, profile | Basic platform operation | 5 |
+| `cms` | Content pages, media library, themes | Content management | 5 |
+| `customers` | Customer database, profiles, segmentation | Customer data management | 4 |
+| `tenancy` | Platform, company, vendor, admin user management | Multi-tenant infrastructure | 4 |
 
-### Optional Modules (10)
+### Optional Modules (11)
 
 Optional modules can be **enabled or disabled per platform**. They provide additional functionality that may not be needed by all platforms.
 
-| Module | Dependencies | Description |
-|--------|--------------|-------------|
-| `cart` | - | Shopping cart management, session-based carts |
-| `catalog` | - | Customer-facing product browsing |
-| `checkout` | `cart`, `orders`, `payments` | Cart-to-order conversion, checkout flow |
-| `payments` | - | Payment gateway integrations (Stripe, PayPal, etc.) |
-| `billing` | `payments` | Platform subscriptions, vendor invoices |
-| `inventory` | - | Stock management, locations |
-| `orders` | `payments` | Order management, customer checkout |
-| `marketplace` | `inventory` | Letzshop integration |
-| `analytics` | - | Reports, dashboards |
-| `messaging` | - | Messages, notifications |
+| Module | Dependencies | Description | Permissions |
+|--------|--------------|-------------|-------------|
+| `analytics` | - | Reports, dashboards | 3 |
+| `billing` | `payments` | Platform subscriptions, vendor invoices | 5 |
+| `cart` | `inventory` | Shopping cart management, session-based carts | 2 |
+| `catalog` | `inventory` | Customer-facing product browsing | 6 |
+| `checkout` | `cart`, `orders`, `payments`, `customers` | Cart-to-order conversion, checkout flow | 2 |
+| `inventory` | - | Stock management, locations | 3 |
+| `loyalty` | `customers` | Stamp/points loyalty programs, wallet integration | 4 |
+| `marketplace` | `inventory` | Letzshop integration | 3 |
+| `messaging` | - | Messages, notifications | 3 |
+| `orders` | `payments` | Order management, customer checkout | 4 |
+| `payments` | - | Payment gateway integrations (Stripe, PayPal, etc.) | 3 |
 
 ### Internal Modules (2)
 
@@ -167,8 +169,8 @@ Each module must have a `definition.py` with a `ModuleDefinition` instance:
 
 ```python
 # app/modules/analytics/definition.py
-from app.modules.base import ModuleDefinition
-from models.database.admin_menu_config import FrontendType
+from app.modules.base import ModuleDefinition, PermissionDefinition
+from app.modules.enums import FrontendType
 
 analytics_module = ModuleDefinition(
     # Identity
@@ -191,6 +193,22 @@ analytics_module = ModuleDefinition(
         "custom_reports",
     ],
 
+    # Module-driven permissions (RBAC)
+    permissions=[
+        PermissionDefinition(
+            id="analytics.view",
+            label_key="analytics.permissions.view",
+            description_key="analytics.permissions.view_desc",
+            category="analytics",
+        ),
+        PermissionDefinition(
+            id="analytics.export",
+            label_key="analytics.permissions.export",
+            description_key="analytics.permissions.export_desc",
+            category="analytics",
+        ),
+    ],
+
     # Menu items per frontend
     menu_items={
         FrontendType.ADMIN: [],  # Analytics uses dashboard
@@ -218,6 +236,7 @@ analytics_module = ModuleDefinition(
 | `version` | `str` | Semantic version (default: "1.0.0") |
 | `requires` | `list[str]` | Module codes this depends on |
 | `features` | `list[str]` | Feature codes for tier gating |
+| `permissions` | `list[PermissionDefinition]` | RBAC permission definitions |
 | `menu_items` | `dict` | Menu items per frontend type |
 | `is_core` | `bool` | Cannot be disabled if True |
 | `is_internal` | `bool` | Admin-only if True |
@@ -929,6 +948,10 @@ The architecture validator (`scripts/validate_architecture.py`) enforces module
 | MOD-017 | ERROR | Services must be in modules, not `app/services/` |
 | MOD-018 | ERROR | Tasks must be in modules, not `app/tasks/` |
 | MOD-019 | ERROR | Schemas must be in modules, not `models/schema/` |
+| MOD-020 | WARNING | Module definition must have required attributes (code, name, description, version, features) |
+| MOD-021 | WARNING | Modules with menus should have features defined |
+| MOD-022 | INFO | Feature modules should have permissions (unless internal or storefront-only) |
+| MOD-023 | INFO | Modules with routers should use `get_*_with_routers` pattern |
 
 Run validation:
 ```bash
diff --git a/docs/development/architecture-rules.md b/docs/development/architecture-rules.md
index 40b161cc..2243acc0 100644
--- a/docs/development/architecture-rules.md
+++ b/docs/development/architecture-rules.md
@@ -850,6 +850,93 @@ Use mobile-first responsive classes.
 
 ---
 
+## Module Structure Rules
+
+Module rules enforce consistent structure and completeness across all modules in `app/modules/`.
+
+### MOD-020: Module Definition Completeness
+**Severity:** Warning
+
+Module definitions should include required attributes: code, name, description, version, and features.
+
+```python
+# ✅ Good - Complete definition
+module = ModuleDefinition(
+    code="billing",
+    name="Billing & Subscriptions",
+    description="Platform subscription management",
+    version="1.0.0",
+    features=["subscription_management", "billing_history"],
+    permissions=[...],
+)
+
+# ❌ Bad - Missing features
+module = ModuleDefinition(
+    code="billing",
+    name="Billing",
+    description="...",
+    version="1.0.0",
+    # Missing features and permissions
+)
+```
+
+### MOD-021: Modules with Menus Should Have Features
+**Severity:** Warning
+
+If a module defines menu items or menu sections, it should also define features.
+
+```python
+# ❌ Bad - Has menus but no features
+module = ModuleDefinition(
+    code="billing",
+    menus={FrontendType.ADMIN: [...]},
+    # Missing features!
+)
+```
+
+### MOD-022: Feature Modules Should Have Permissions
+**Severity:** Info
+
+Modules with features should define permissions for RBAC, unless:
+- `is_internal=True` (internal tools)
+- Storefront-only module (session-based, no admin UI)
+
+```python
+# ✅ Good - Features with permissions
+module = ModuleDefinition(
+    code="billing",
+    features=["subscription_management"],
+    permissions=[
+        PermissionDefinition(
+            id="billing.view_subscriptions",
+            label_key="billing.permissions.view_subscriptions",
+            description_key="billing.permissions.view_subscriptions_desc",
+            category="billing",
+        ),
+    ],
+)
+```
+
+### MOD-023: Router Pattern Consistency
+**Severity:** Info
+
+Modules with routers should use the `get_*_with_routers()` pattern for lazy imports.
+
+```python
+# ✅ Good - Lazy router pattern
+def _get_admin_router():
+    from app.modules.billing.routes.api.admin import admin_router
+    return admin_router
+
+def get_billing_module_with_routers() -> ModuleDefinition:
+    billing_module.admin_router = _get_admin_router()
+    return billing_module
+```
+
+See [Module System Architecture](../architecture/module-system.md) for complete MOD-001 to MOD-019 rules.
+
+---
+
 ## Security & Multi-Tenancy Rules
 
 ### Multi-Tenancy Rules
@@ -1030,20 +1117,21 @@ All rules are defined in `.architecture-rules.yaml`. To modify rules:
 
 ## Summary Statistics
 
-| Category | Rules | Errors | Warnings |
-|----------|-------|--------|----------|
-| Backend | 20 | 15 | 5 |
-| Frontend JS | 7 | 6 | 1 |
-| Frontend Templates | 8 | 4 | 4 |
-| Frontend Macros | 5 | 2 | 3 |
-| Frontend Components | 1 | 0 | 1 |
-| Frontend Styling | 4 | 1 | 3 |
-| Naming | 5 | 3 | 2 |
-| Security | 5 | 5 | 0 |
-| Quality | 3 | 2 | 1 |
-| **Total** | **58** | **38** | **20** |
+| Category | Rules | Errors | Warnings | Info |
+|----------|-------|--------|----------|------|
+| Backend | 20 | 15 | 5 | 0 |
+| Module Structure | 23 | 7 | 10 | 6 |
+| Frontend JS | 7 | 6 | 1 | 0 |
+| Frontend Templates | 8 | 4 | 4 | 0 |
+| Frontend Macros | 5 | 2 | 3 | 0 |
+| Frontend Components | 1 | 0 | 1 | 0 |
+| Frontend Styling | 4 | 1 | 3 | 0 |
+| Naming | 5 | 3 | 2 | 0 |
+| Security | 5 | 5 | 0 | 0 |
+| Quality | 3 | 2 | 1 | 0 |
+| **Total** | **81** | **45** | **30** | **6** |
 
 ---
 
-**Last Updated:** 2025-12-21
-**Version:** 2.4
+**Last Updated:** 2026-02-02
+**Version:** 2.5
diff --git a/scripts/validate_architecture.py b/scripts/validate_architecture.py
index 85c000dc..b719c4b3 100755
--- a/scripts/validate_architecture.py
+++ b/scripts/validate_architecture.py
@@ -4351,6 +4351,117 @@ class ArchitectureValidator:
                     suggestion="Create 'exceptions.py' or 'exceptions/__init__.py'",
                 )
 
+        # MOD-020: Check module definition has required attributes
+        self._validate_module_definition_completeness(module_dir, module_name, definition_file, definition_content)
+
+    def _validate_module_definition_completeness(
+        self,
+        module_dir: Path,
+        module_name: str,
+        definition_file: Path,
+        definition_content: str
+    ):
+        """
+        Validate module definition completeness (MOD-020 to MOD-023).
+
+        Checks:
+        - MOD-020: Required attributes (code, name, description, version, features, permissions)
+        - MOD-021: Modules with menus should have features
+        - MOD-022: Feature modules should have permissions
+        - MOD-023: Modules with routers should use get_*_with_routers pattern
+        """
+        # Detect module characteristics
+        is_internal = "is_internal=True" in definition_content or "is_internal = True" in definition_content
+        is_core_infrastructure = (
+            ("is_core=True" in definition_content or "is_core = True" in definition_content) and
+            ("menu_items={}" in definition_content or "menu_items = {}" in definition_content or "menu_items" not in definition_content)
+        )
+
+        has_features = "features=[" in definition_content or "features = [" in definition_content
+        has_permissions = "permissions=[" in definition_content or "permissions = [" in definition_content
+        has_menus = "menus={" in definition_content or "menus = {" in definition_content
+        has_menu_items = (
+            "menu_items={" in definition_content and
+            not re.search(r"menu_items\s*=\s*\{\s*\}", definition_content)
+        )
+
+        # Check for router lazy import pattern
+        has_router_imports = "_get_admin_router" in definition_content or "_get_vendor_router" in definition_content
+        has_get_with_routers = re.search(r"def get_\w+_module_with_routers\s*\(", definition_content)
+
+        # MOD-020: Check required attributes
+        # Basic required attributes
+        required_attrs = ["code=", "name=", "description=", "version="]
+        for attr in required_attrs:
+            if attr not in definition_content:
+                attr_name = attr.replace("=", "")
+                self._add_violation(
+                    rule_id="MOD-020",
+                    rule_name="Module definition must have required attributes",
+                    severity=Severity.WARNING,
+                    file_path=definition_file,
+                    line_number=1,
+                    message=f"Module '{module_name}' missing required attribute '{attr_name}'",
+                    context="ModuleDefinition()",
+                    suggestion=f"Add '{attr_name}' to ModuleDefinition",
+                )
+
+        # Check features (unless infrastructure module)
+        if not has_features and not is_core_infrastructure:
+            self._add_violation(
+                rule_id="MOD-020",
+                rule_name="Module definition must have required attributes",
+                severity=Severity.WARNING,
+                file_path=definition_file,
+                line_number=1,
+                message=f"Module '{module_name}' missing 'features' list",
+                context="ModuleDefinition() without features",
+                suggestion="Add 'features=[...]' to describe module capabilities",
+            )
+
+        # MOD-021: Modules with menus should have features
+        if (has_menus or has_menu_items) and not has_features:
+            self._add_violation(
+                rule_id="MOD-021",
+                rule_name="Modules with menus should have features",
+                severity=Severity.WARNING,
+                file_path=definition_file,
+                line_number=1,
+                message=f"Module '{module_name}' has menus but no features defined",
+                context="menus={...} without features=[...]",
+                suggestion="Add 'features=[...]' to describe what the module provides",
+            )
+
+        # MOD-022: Feature modules should have permissions
+        if has_features and not has_permissions and not is_internal:
+            # Check if it's a storefront-only module (cart, checkout)
+            is_storefront_only = module_name in ["cart", "checkout"]
+
+            if not is_storefront_only:
+                self._add_violation(
+                    rule_id="MOD-022",
+                    rule_name="Feature modules should have permissions",
+                    severity=Severity.INFO,
+                    file_path=definition_file,
+                    line_number=1,
+                    message=f"Module '{module_name}' has features but no permissions defined",
+                    context="features=[...] without permissions=[...]",
+                    suggestion="Add 'permissions=[PermissionDefinition(...), ...]' for RBAC",
+                )
+
+        # MOD-023: Modules with routers should use get_*_with_routers pattern
+        if has_router_imports and not has_get_with_routers:
+            self._add_violation(
+                rule_id="MOD-023",
+                rule_name="Modules with routers should use get_*_with_routers pattern",
+                severity=Severity.INFO,
+                file_path=definition_file,
+                line_number=1,
+                message=f"Module '{module_name}' has router imports but no get_*_with_routers() function",
+                context="_get_admin_router() or _get_vendor_router() without wrapper",
+                suggestion=f"Add 'def get_{module_name}_module_with_routers()' function",
+            )
+
     def _validate_legacy_locations(self, target_path: Path):
         """
         Validate that code is not in legacy locations (MOD-016 to MOD-019).
diff --git a/static/public/css/.gitkeep b/static/platform/css/.gitkeep
similarity index 100%
rename from static/public/css/.gitkeep
rename to static/platform/css/.gitkeep
diff --git a/static/public/css/tailwind.css b/static/platform/css/tailwind.css
similarity index 100%
rename from static/public/css/tailwind.css
rename to static/platform/css/tailwind.css
diff --git a/static/public/css/tailwind.output.css b/static/platform/css/tailwind.output.css
similarity index 100%
rename from static/public/css/tailwind.output.css
rename to static/platform/css/tailwind.output.css
diff --git a/static/public/img/.gitkeep b/static/platform/img/.gitkeep
similarity index 100%
rename from static/public/img/.gitkeep
rename to static/platform/img/.gitkeep
diff --git a/static/public/js/.gitkeep b/static/platform/js/.gitkeep
similarity index 100%
rename from static/public/js/.gitkeep
rename to static/platform/js/.gitkeep
diff --git a/tests/integration/api/v1/public/README.md b/tests/integration/api/v1/platform/README.md
similarity index 100%
rename from tests/integration/api/v1/public/README.md
rename to tests/integration/api/v1/platform/README.md
diff --git a/tests/integration/api/v1/public/__init__.py b/tests/integration/api/v1/platform/__init__.py
similarity index 100%
rename from tests/integration/api/v1/public/__init__.py
rename to tests/integration/api/v1/platform/__init__.py
diff --git a/tests/integration/api/v1/public/test_letzshop_vendors.py b/tests/integration/api/v1/platform/test_letzshop_vendors.py
similarity index 100%
rename from tests/integration/api/v1/public/test_letzshop_vendors.py
rename to tests/integration/api/v1/platform/test_letzshop_vendors.py
diff --git a/tests/integration/api/v1/public/test_pricing.py b/tests/integration/api/v1/platform/test_pricing.py
similarity index 100%
rename from tests/integration/api/v1/public/test_pricing.py
rename to tests/integration/api/v1/platform/test_pricing.py
diff --git a/tests/integration/api/v1/public/test_signup.py b/tests/integration/api/v1/platform/test_signup.py
similarity index 100%
rename from tests/integration/api/v1/public/test_signup.py
rename to tests/integration/api/v1/platform/test_signup.py
diff --git a/tests/unit/modules/__init__.py b/tests/unit/modules/__init__.py
new file mode 100644
index 00000000..3b797624
--- /dev/null
+++ b/tests/unit/modules/__init__.py
@@ -0,0 +1,2 @@
+# tests/unit/modules/__init__.py
+"""Unit tests for module system."""
diff --git a/tests/unit/modules/test_module_definitions.py b/tests/unit/modules/test_module_definitions.py
new file mode 100644
index 00000000..786b8229
--- /dev/null
+++ b/tests/unit/modules/test_module_definitions.py
@@ -0,0 +1,315 @@
+# tests/unit/modules/test_module_definitions.py
+"""
+Unit tests for module definitions.
+
+Tests cover:
+- Module definition completeness (MOD-020)
+- Menu/feature consistency (MOD-021)
+- Permission coverage (MOD-022)
+- Router pattern consistency (MOD-023)
+"""
+
+import pytest
+
+from app.modules.registry import MODULES
+from app.modules.base import ModuleDefinition, PermissionDefinition
+
+
+@pytest.mark.unit
+class TestModuleDefinitionCompleteness:
+    """Test MOD-020: Module definitions have required attributes."""
+
+    def test_all_modules_have_code(self):
+        """Test that all modules have a code defined."""
+        for code, module in MODULES.items():
+            assert module.code, f"Module {code} missing 'code' attribute"
+            assert module.code == code, f"Module code mismatch: {module.code} != {code}"
+
+    def test_all_modules_have_name(self):
+        """Test that all modules have a name defined."""
+        for code, module in MODULES.items():
+            assert module.name, f"Module {code} missing 'name' attribute"
+
+    def test_all_modules_have_description(self):
+        """Test that all modules have a description defined."""
+        for code, module in MODULES.items():
+            assert module.description, f"Module {code} missing 'description' attribute"
+
+    def test_all_modules_have_version(self):
+        """Test that all modules have a version defined."""
+        for code, module in MODULES.items():
+            assert module.version, f"Module {code} missing 'version' attribute"
+            # Version should be semantic versioning format
+            parts = module.version.split(".")
+            assert len(parts) >= 2, f"Module {code} has invalid version format: {module.version}"
+
+    def test_all_modules_have_features(self):
+        """Test that all modules have features defined."""
+        for code, module in MODULES.items():
+            assert module.features is not None, f"Module {code} missing 'features' attribute"
+            assert isinstance(module.features, list), f"Module {code} features should be a list"
+            # All modules should have at least one feature
+            assert len(module.features) > 0, f"Module {code} has empty features list"
+
+
+@pytest.mark.unit
+class TestModulePermissions:
+    """Test MOD-022: Feature modules should have permissions."""
+
+    # Modules exempt from permission requirements
+    EXEMPT_MODULES = {
+        "contracts",  # Infrastructure module
+        "dev-tools",  # Internal module (is_internal=True)
+        "monitoring",  # Internal module (is_internal=True)
+    }
+
+    def test_feature_modules_have_permissions(self):
+        """Test that modules with features have permissions (unless exempt)."""
+        for code, module in MODULES.items():
+            if code in self.EXEMPT_MODULES:
+                continue
+
+            # If module has features, it should have permissions
+            if module.features:
+                assert module.permissions is not None, (
+                    f"Module {code} has features but no permissions"
+                )
+                assert len(module.permissions) > 0, (
+                    f"Module {code} has features but empty permissions list"
+                )
+
+    def test_internal_modules_exempt_from_permissions(self):
+        """Test that internal modules don't require permissions."""
+        internal_modules = [m for m in MODULES.values() if getattr(m, "is_internal", False)]
+        # Internal modules exist
+        assert len(internal_modules) > 0, "No internal modules found"
+        # They may or may not have permissions (exempt from requirement)
+
+    def test_permission_structure(self):
+        """Test that permissions have required fields."""
+        for code, module in MODULES.items():
+            if not module.permissions:
+                continue
+
+            for perm in module.permissions:
+                assert isinstance(perm, PermissionDefinition), (
+                    f"Module {code} permission is not a PermissionDefinition"
+                )
+                assert perm.id, f"Module {code} has permission without id"
+                assert perm.label_key, f"Module {code} permission {perm.id} missing label_key"
+                assert perm.description_key, (
+                    f"Module {code} permission {perm.id} missing description_key"
+                )
+                assert perm.category, f"Module {code} permission {perm.id} missing category"
+
+    def test_permission_ids_follow_convention(self):
+        """Test that permission IDs follow the module.action convention."""
+        for code, module in MODULES.items():
+            if not module.permissions:
+                continue
+
+            for perm in module.permissions:
+                # Permission ID should contain a dot
+                assert "." in perm.id, (
+                    f"Module {code} permission {perm.id} should follow 'module.action' format"
+                )
+
+    def test_permission_counts(self):
+        """Test that modules have expected permission counts."""
+        # Modules that should have permissions
+        modules_with_permissions = {
+            code: module
+            for code, module in MODULES.items()
+            if module.permissions
+        }
+
+        # At least 15 modules should have permissions
+        assert len(modules_with_permissions) >= 15, (
+            f"Expected at least 15 modules with permissions, got {len(modules_with_permissions)}"
+        )
+
+
+@pytest.mark.unit
+class TestModuleMenuFeatureConsistency:
+    """Test MOD-021: Modules with menus should have features."""
+
+    def test_modules_with_menus_have_features(self):
+        """Test that modules with menu definitions have features."""
+        for code, module in MODULES.items():
+            has_menus = getattr(module, "menus", None) and len(module.menus) > 0
+            has_menu_items = (
+                getattr(module, "menu_items", None) and
+                any(items for items in module.menu_items.values())
+            )
+
+            if has_menus or has_menu_items:
+                assert module.features and len(module.features) > 0, (
+                    f"Module {code} has menus but no features defined"
+                )
+
+
+@pytest.mark.unit
+class TestModuleRouterPattern:
+    """Test MOD-023: Router pattern consistency."""
+
+    def test_modules_with_routers_attribute(self):
+        """Test that modules can have router attributes attached."""
+        # After calling get_*_with_routers(), modules should have router attrs
+        # This test just verifies the attribute exists (may be None)
+        for code, module in MODULES.items():
+            # These are optional attributes set by get_*_with_routers()
+            # Just verify they can be accessed without error
+            _ = getattr(module, "admin_router", None)
+            _ = getattr(module, "vendor_router", None)
+            _ = getattr(module, "platform_router", None)
+
+
+@pytest.mark.unit
+class TestSpecificModulePermissions:
+    """Test specific modules have their expected permissions."""
+
+    def test_cart_module_permissions(self):
+        """Test cart module has required permissions."""
+        module = MODULES.get("cart")
+        assert module is not None
+        assert module.permissions is not None
+
+        perm_ids = {p.id for p in module.permissions}
+        assert "cart.view" in perm_ids
+        assert "cart.manage" in perm_ids
+
+    def test_checkout_module_permissions(self):
+        """Test checkout module has required permissions."""
+        module = MODULES.get("checkout")
+        assert module is not None
+        assert module.permissions is not None
+
+        perm_ids = {p.id for p in module.permissions}
+        assert "checkout.view_settings" in perm_ids
+        assert "checkout.manage_settings" in perm_ids
+
+    def test_analytics_module_permissions(self):
+        """Test analytics module has required permissions."""
+        module = MODULES.get("analytics")
+        assert module is not None
+        assert module.permissions is not None
+
+        perm_ids = {p.id for p in module.permissions}
+        assert "analytics.view" in perm_ids
+        assert "analytics.export" in perm_ids
+        assert "analytics.manage_dashboards" in perm_ids
+
+    def test_billing_module_permissions(self):
+        """Test billing module has required permissions."""
+        module = MODULES.get("billing")
+        assert module is not None
+        assert module.permissions is not None
+
+        perm_ids = {p.id for p in module.permissions}
+        assert "billing.view_tiers" in perm_ids
+        assert "billing.manage_tiers" in perm_ids
+        assert "billing.view_subscriptions" in perm_ids
+        assert "billing.manage_subscriptions" in perm_ids
+        assert "billing.view_invoices" in perm_ids
+
+    def test_cms_module_permissions(self):
+        """Test cms module has required permissions."""
+        module = MODULES.get("cms")
+        assert module is not None
+        assert module.permissions is not None
+
+        perm_ids = {p.id for p in module.permissions}
+        assert "cms.view_pages" in perm_ids
+        assert "cms.manage_pages" in perm_ids
+        assert "cms.view_media" in perm_ids
+        assert "cms.manage_media" in perm_ids
+        assert "cms.manage_themes" in perm_ids
+
+    def test_loyalty_module_permissions(self):
+        """Test loyalty module has required permissions."""
+        module = MODULES.get("loyalty")
+        assert module is not None
+        assert module.permissions is not None
+
+        perm_ids = {p.id for p in module.permissions}
+        assert "loyalty.view_programs" in perm_ids
+        assert "loyalty.manage_programs" in perm_ids
+        assert "loyalty.view_rewards" in perm_ids
+        assert "loyalty.manage_rewards" in perm_ids
+
+    def test_marketplace_module_permissions(self):
+        """Test marketplace module has required permissions."""
+        module = MODULES.get("marketplace")
+        assert module is not None
+        assert module.permissions is not None
+
+        perm_ids = {p.id for p in module.permissions}
+        assert "marketplace.view_integration" in perm_ids
+        assert "marketplace.manage_integration" in perm_ids
+        assert "marketplace.sync_products" in perm_ids
+
+    def test_messaging_module_permissions(self):
+        """Test messaging module has required permissions."""
+        module = MODULES.get("messaging")
+        assert module is not None
+        assert module.permissions is not None
+
+        perm_ids = {p.id for p in module.permissions}
+        assert "messaging.view_messages" in perm_ids
+        assert "messaging.send_messages" in perm_ids
+        assert "messaging.manage_templates" in perm_ids
+
+    def test_payments_module_permissions(self):
+        """Test payments module has required permissions."""
+        module = MODULES.get("payments")
+        assert module is not None
+        assert module.permissions is not None
+
+        perm_ids = {p.id for p in module.permissions}
+        assert "payments.view_gateways" in perm_ids
+        assert "payments.manage_gateways" in perm_ids
+        assert "payments.view_transactions" in perm_ids
+
+
+@pytest.mark.unit
+class TestModuleFeatures:
+    """Test module feature definitions."""
+
+    def test_cart_module_features(self):
+        """Test cart module has required features."""
+        module = MODULES.get("cart")
+        assert module is not None
+
+        expected_features = {
+            "cart_management",
+            "cart_persistence",
+            "cart_item_operations",
+            "shipping_calculation",
+            "promotion_application",
+        }
+        assert expected_features.issubset(set(module.features))
+
+    def test_checkout_module_features(self):
+        """Test checkout module has required features."""
+        module = MODULES.get("checkout")
+        assert module is not None
+
+        expected_features = {
+            "checkout_flow",
+            "order_creation",
+            "payment_processing",
+            "checkout_validation",
+            "guest_checkout",
+        }
+        assert expected_features.issubset(set(module.features))
+
+    def test_catalog_module_features(self):
+        """Test catalog module has required features."""
+        module = MODULES.get("catalog")
+        assert module is not None
+
+        expected_features = {
+            "product_catalog",
+            "product_search",
+        }
+        assert expected_features.issubset(set(module.features))