diff --git a/eslint.config.mjs b/eslint.config.mjs
index 84578b3..2e6ddf5 100755
--- a/eslint.config.mjs
+++ b/eslint.config.mjs
@@ -6,8 +6,33 @@ import { fileURLToPath } from "url";
 const __filename = fileURLToPath(import.meta.url);
 const __dirname = dirname(__filename);
 
+// PRD §5.4: Module boundaries —
+// (a) cross-module imports only via index.ts
+// (b) infrastructure never imports modules
+// (c) modules never import routes or UI
+const MODULE_BOUNDARY_RULE = {
+  // Prevent direct imports between modules (must go through index.ts)
+  "no-restricted-imports": ["error", {
+    patterns: [
+      // Module → Module direct import (must use index.ts)
+      {
+        group: ["@/components/aos/views/*"],
+        message: "Views must not import other views directly. Use shared primitives instead."
+      },
+      // Infrastructure → Module (infrastructure should not depend on modules)
+      {
+        group: ["@/components/aos/views/*", "@/components/aos/portal-*"],
+        message: "Infrastructure code must not import UI views."
+      },
+    ],
+  }],
+};
+
 const eslintConfig = [...nextCoreWebVitals, ...nextTypescript, {
   rules: {
+    // PRD §5.4: Module boundary enforcement
+    ...MODULE_BOUNDARY_RULE,
+
     // TypeScript rules
     "@typescript-eslint/no-explicit-any": "off",
     "@typescript-eslint/no-unused-vars": "off",
@@ -15,7 +40,7 @@ const eslintConfig = [...nextCoreWebVitals, ...nextTypescript, {
     "@typescript-eslint/ban-ts-comment": "off",
     "@typescript-eslint/prefer-as-const": "off",
     "@typescript-eslint/no-unused-disable-directive": "off",
-    
+
     // React rules
     "react-hooks/exhaustive-deps": "off",
     "react-hooks/purity": "off",
@@ -23,11 +48,11 @@ const eslintConfig = [...nextCoreWebVitals, ...nextTypescript, {
     "react/display-name": "off",
     "react/prop-types": "off",
     "react-compiler/react-compiler": "off",
-    
+
     // Next.js rules
     "@next/next/no-img-element": "off",
     "@next/next/no-html-link-for-pages": "off",
-    
+
     // General JavaScript rules
     "prefer-const": "off",
     "no-unused-vars": "off",
@@ -44,7 +69,7 @@ const eslintConfig = [...nextCoreWebVitals, ...nextTypescript, {
     "no-useless-escape": "off",
   },
 }, {
-  ignores: ["node_modules/**", ".next/**", "out/**", "build/**", "next-env.d.ts", "examples/**", "skills"]
+  ignores: ["node_modules/**", ".next/**", "out/**", "build/**", "next-env.d.ts", "examples/**", "skills"],
 }];
 
 export default eslintConfig;