diff --git a/LangSpec2/src/org/lara/langspec2/validation/SpecValidator.java b/LangSpec2/src/org/lara/langspec2/validation/SpecValidator.java
index 6cf0f8f3f..92a530ee8 100644
--- a/LangSpec2/src/org/lara/langspec2/validation/SpecValidator.java
+++ b/LangSpec2/src/org/lara/langspec2/validation/SpecValidator.java
@@ -35,6 +35,7 @@ public static List<String> collectErrors(WeaverModel model) {
         checkNoSelfTypeInTypeDefs(model, errors);
         checkReservedKeywords(model, errors);
         checkDefaultAttributes(model, errors);
+        checkEnumDisplays(model, errors);
 
         return errors;
     }
@@ -209,5 +210,18 @@ private static void checkDefaultAttributes(WeaverModel model, List<String> error
         }
     }
 
+    private static void checkEnumDisplays(WeaverModel model, List<String> errors) {
+        for (var ed : model.getEnumDefs().values()) {
+            var displays = new HashSet<String>();
+            for (var value : ed.values()) {
+                var display = value.display() != null ? value.display() : value.value();
+                if (!displays.add(display)) {
+                    errors.add("Duplicate display '" + display + "' in enum '" + ed.name()
+                            + "': fromDisplay() resolves to the first constant, making the other one unreachable");
+                }
+            }
+        }
+    }
+
     private record MemberSignature(String name, List<JpDataType> paramTypes) {}
 }
diff --git a/LangSpec2/test/org/lara/langspec2/validation/SpecValidatorTest.java b/LangSpec2/test/org/lara/langspec2/validation/SpecValidatorTest.java
new file mode 100644
index 000000000..9c07f3be0
--- /dev/null
+++ b/LangSpec2/test/org/lara/langspec2/validation/SpecValidatorTest.java
@@ -0,0 +1,44 @@
+package org.lara.langspec2.validation;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+import org.lara.langspec2.model.EnumDef;
+import org.lara.langspec2.model.EnumValue;
+import org.lara.langspec2.model.JpClass;
+import org.lara.langspec2.model.WeaverModel;
+
+class SpecValidatorTest {
+
+    private static WeaverModel newModel() {
+        return new WeaverModel("Prefix", "example.pkg", new JpClass("global"));
+    }
+
+    @Test
+    void duplicateDisplaysInEnumAreReported() {
+        var model = newModel();
+        model.addEnumDef(new EnumDef("Kind", List.of(
+                new EnumValue("A"),
+                new EnumValue("B"),
+                new EnumValue("C", "A"))));
+
+        var errors = SpecValidator.collectErrors(model);
+
+        assertThat(errors).anyMatch(error -> error.contains("Duplicate display 'A' in enum 'Kind'"));
+    }
+
+    @Test
+    void distinctDisplaysInEnumAreAccepted() {
+        var model = newModel();
+        model.addEnumDef(new EnumDef("Kind", List.of(
+                new EnumValue("A"),
+                new EnumValue("B"),
+                new EnumValue("C", "c"))));
+
+        var errors = SpecValidator.collectErrors(model);
+
+        assertThat(errors).isEmpty();
+    }
+}
diff --git a/Lara-JS/code/generate-ts-joinpoints.test.ts b/Lara-JS/code/generate-ts-joinpoints.test.ts
new file mode 100644
index 000000000..9317e6869
--- /dev/null
+++ b/Lara-JS/code/generate-ts-joinpoints.test.ts
@@ -0,0 +1,49 @@
+import fs from "fs";
+import os from "os";
+import path from "path";
+import { generateEnums } from "../scripts/generate-ts-joinpoints.ts";
+
+describe("generateEnums", () => {
+  it("preserves the enum values from the language specification", () => {
+    const outputDirectory = fs.mkdtempSync(
+      path.join(os.tmpdir(), "lara-build-interfaces-"),
+    );
+    const outputPath = path.join(outputDirectory, "Joinpoints.ts");
+
+    try {
+      const outputFile = fs.openSync(outputPath, "w");
+      try {
+        generateEnums(
+          [
+            {
+              name: "StorageClass",
+              entries: [
+                { name: "NONE", value: "NONE" },
+                { name: "PRIVATE_EXTERN", value: "PRIVATE_EXTERN" },
+                { name: "STATIC", value: "STATIC" },
+              ],
+            },
+            {
+              name: "AccessSpecifier",
+              entries: [
+                { name: "DEFAULT", value: "DEFAULT" },
+                { name: "STATIC", value: "static" },
+              ],
+            },
+          ],
+          outputFile,
+        );
+      } finally {
+        fs.closeSync(outputFile);
+      }
+
+      const output = fs.readFileSync(outputPath, "utf8");
+      expect(output).toContain('  STATIC: "STATIC",');
+      expect(output).toContain('  PRIVATE_EXTERN: "PRIVATE_EXTERN",');
+      expect(output).toContain('export const AccessSpecifier = {');
+      expect(output).toContain('  STATIC: "static",');
+    } finally {
+      fs.rmSync(outputDirectory, { recursive: true, force: true });
+    }
+  });
+});
diff --git a/Lara-JS/scripts/convert-joinpoint-specification.ts b/Lara-JS/scripts/convert-joinpoint-specification.ts
index 2195a25ac..ac10536f6 100644
--- a/Lara-JS/scripts/convert-joinpoint-specification.ts
+++ b/Lara-JS/scripts/convert-joinpoint-specification.ts
@@ -32,7 +32,7 @@ type JSON_EnumSpecification = {
   type: "enum";
   name: string;
   extends?: string;
-  children: { value: string }[];
+  children: { value: string; display?: string }[];
 };
 
 export type ConvertedSpecification = {
@@ -74,7 +74,7 @@ export type ConvertedParameter = {
 export type ConvertedEnum = {
   name: string;
   extends?: string;
-  entries: string[];
+  entries: { name: string; value: string }[];
 };
 
 export function convertSpecification(input: JSON_LanguageSpecification, baseJoinPointSpec?: ConvertedSpecification | undefined): ConvertedSpecification {
@@ -367,7 +367,7 @@ function convertEnum(e: JSON_EnumSpecification): ConvertedEnum {
     name: e.name,
     extends: e.extends,
     entries: e.children.map((child) => {
-      return child.value;
+      return { name: child.value, value: child.display ?? child.value };
     }),
   };
 }
diff --git a/Lara-JS/scripts/generate-ts-joinpoints.ts b/Lara-JS/scripts/generate-ts-joinpoints.ts
index 9d6dbe111..8428b9718 100644
--- a/Lara-JS/scripts/generate-ts-joinpoints.ts
+++ b/Lara-JS/scripts/generate-ts-joinpoints.ts
@@ -207,7 +207,7 @@ function generateEnum(e: ConvertedEnum, outputFile: number) {
  */\n`);
   fs.writeSync(outputFile, `export const ${e.name} = {\n`);
   e.entries.forEach((entry) => {
-    fs.writeSync(outputFile, `  ${entry}: "${entry.toLowerCase()}",\n`);
+    fs.writeSync(outputFile, `  ${entry.name}: "${entry.value}",\n`);
   });
   fs.writeSync(outputFile, `} as const;\n`);
   fs.writeSync(
diff --git a/LaraUtils/test/pt/up/fe/specs/lara/LaraSystemToolsTest.java b/LaraUtils/test/pt/up/fe/specs/lara/LaraSystemToolsTest.java
index b637071dd..80f81ca4f 100644
--- a/LaraUtils/test/pt/up/fe/specs/lara/LaraSystemToolsTest.java
+++ b/LaraUtils/test/pt/up/fe/specs/lara/LaraSystemToolsTest.java
@@ -126,7 +126,7 @@ void testRunCommand_withNullTimeout_handlesGracefully() {
         // Given
         String command = "echo hello";
         boolean printToConsole = false;
-        long timeoutNanos = 2000000000; // 2 seconds
+        Long timeoutNanos = null;
         
         // When
         ProcessOutputAsString result = LaraSystemTools.runCommand(command, workingDirectory, printToConsole, timeoutNanos);