diff --git a/src/bin/keycloakify/BuildOptions.ts b/src/bin/keycloakify/BuildOptions.ts
index 52ddc14c..9c1a72f5 100644
--- a/src/bin/keycloakify/BuildOptions.ts
+++ b/src/bin/keycloakify/BuildOptions.ts
@@ -4,9 +4,10 @@ import type { Equals } from "tsafe";
 import { id } from "tsafe/id";
 import { parse as urlParse } from "url";
 import { typeGuard } from "tsafe/typeGuard";
+import { symToStr } from "tsafe/symToStr";
 
-const BUNDLERS = ["mvn", "keycloakify", "none"] as const;
-type Bundler = typeof BUNDLERS[number];
+const bundlers = ["mvn", "keycloakify", "none"] as const;
+type Bundler = typeof bundlers[number];
 type ParsedPackageJson = {
     name: string;
     version: string;
@@ -32,7 +33,7 @@ const zParsedPackageJson = z.object({
             "areAppAndKeycloakServerSharingSameDomain": z.boolean().optional(),
             "artifactId": z.string().optional(),
             "groupId": z.string().optional(),
-            "bundler": z.enum(BUNDLERS).optional()
+            "bundler": z.enum(bundlers).optional()
         })
         .optional()
 });
@@ -51,7 +52,7 @@ export namespace BuildOptions {
         extraThemeProperties?: string[];
         groupId: string;
         artifactId?: string;
-        bundler?: Bundler;
+        bundler: Bundler;
     };
 
     export type Standalone = Common & {
@@ -133,11 +134,12 @@ export function readBuildOptions(params: {
                 assert(
                     typeGuard<Bundler | undefined>(
                         KEYCLOAKIFY_BUNDLER,
-                        KEYCLOAKIFY_BUNDLER === undefined || id<readonly string[]>(BUNDLERS).includes(KEYCLOAKIFY_BUNDLER)
-                    )
+                        [undefined, ...id<readonly string[]>(bundlers)].includes(KEYCLOAKIFY_BUNDLER)
+                    ),
+                    `${symToStr({ KEYCLOAKIFY_BUNDLER })} should be one of ${bundlers.join(", ")}`
                 );
 
-                return KEYCLOAKIFY_BUNDLER ?? bundler;
+                return KEYCLOAKIFY_BUNDLER ?? bundler ?? "keycloakify";
             })(),
             "artifactId": process.env.KEYCLOAKIFY_ARTIFACT_ID ?? artifactId,
             "groupId": (() => {
diff --git a/src/bin/keycloakify/keycloakify.ts b/src/bin/keycloakify/keycloakify.ts
index 2f3f1d77..119e9c2d 100644
--- a/src/bin/keycloakify/keycloakify.ts
+++ b/src/bin/keycloakify/keycloakify.ts
@@ -8,6 +8,8 @@ import { readBuildOptions } from "./BuildOptions";
 import { getLogger } from "../tools/logger";
 import { getCliOptions } from "../tools/cliOptions";
 import jar from "../tools/jar";
+import { assert } from "tsafe/assert";
+import type { Equals } from "tsafe";
 
 const reactProjectDirPath = process.cwd();
 
@@ -51,22 +53,26 @@ export async function main() {
         buildOptions
     });
 
-    if (buildOptions.bundler === "none") {
-        logger.log("😱 Skipping bundling step, there will be no jar");
-    } else if (buildOptions.bundler === "keycloakify") {
-        logger.log("🫶 Let keycloakify do its thang");
-        await jar({
-            "rootPath": keycloakThemeBuildingDirPath,
-            "version": buildOptions.version,
-            "groupId": buildOptions.groupId,
-            "artifactId": buildOptions.artifactId || `${buildOptions.themeName}-keycloak-theme`,
-            "targetPath": jarFilePath
-        });
-    } else {
-        logger.log("🫙 Run maven to deliver a jar");
-        child_process.execSync("mvn package", {
-            "cwd": keycloakThemeBuildingDirPath
-        });
+    switch (buildOptions.bundler) {
+        case "none":
+            logger.log("😱 Skipping bundling step, there will be no jar");
+            break;
+        case "keycloakify":
+            logger.log("🫶 Let keycloakify do its thang");
+            await jar({
+                "rootPath": keycloakThemeBuildingDirPath,
+                "version": buildOptions.version,
+                "groupId": buildOptions.groupId,
+                "artifactId": buildOptions.artifactId || `${buildOptions.themeName}-keycloak-theme`,
+                "targetPath": jarFilePath
+            });
+            break;
+        case "mvn":
+            logger.log("🫙 Run maven to deliver a jar");
+            child_process.execSync("mvn package", { "cwd": keycloakThemeBuildingDirPath });
+            break;
+        default:
+            assert<Equals<typeof buildOptions.bundler, never>>(false);
     }
 
     // We want, however, to test in a container running the latest Keycloak version