diff --git a/packages/twenty-sdk/src/cli/__tests__/bundle/__integration__/cli-esm-bundle-startup.integration.spec.ts b/packages/twenty-sdk/src/cli/__tests__/bundle/__integration__/cli-esm-bundle-startup.integration.spec.ts
new file mode 100644
index 0000000000..946710d27b
--- /dev/null
+++ b/packages/twenty-sdk/src/cli/__tests__/bundle/__integration__/cli-esm-bundle-startup.integration.spec.ts
@@ -0,0 +1,36 @@
+import { spawnSync } from 'node:child_process';
+import { existsSync } from 'node:fs';
+import { dirname, resolve } from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+const currentDir = dirname(fileURLToPath(import.meta.url));
+const packageRoot = resolve(currentDir, '../../../../..');
+const bundledCliEntry = resolve(packageRoot, 'dist/cli.mjs');
+const isBundleBuilt = existsSync(bundledCliEntry);
+
+describe('CLI ESM bundle startup', () => {
+  const runOrSkip = isBundleBuilt || process.env.CI ? it : it.skip;
+
+  runOrSkip(
+    'runs `--help` from the bundled .mjs entry without a CJS-in-ESM crash',
+    () => {
+      if (!isBundleBuilt) {
+        throw new Error(
+          `Expected the built ESM entry at ${bundledCliEntry}. Run \`npx nx build twenty-sdk\` before this test.`,
+        );
+      }
+
+      const result = spawnSync('node', [bundledCliEntry, '--help'], {
+        encoding: 'utf8',
+        timeout: 30_000,
+      });
+
+      const combinedOutput = `${result.stdout ?? ''}\n${result.stderr ?? ''}`;
+
+      expect(combinedOutput).not.toMatch(/Calling `require` for/);
+      expect(combinedOutput).not.toMatch(/is not defined in ES module scope/);
+      expect(result.status).toBe(0);
+      expect(result.stdout).toContain('Usage: twenty');
+    },
+  );
+});
diff --git a/packages/twenty-sdk/vite.config.node.ts b/packages/twenty-sdk/vite.config.node.ts
index c2e62939bd..887d82131b 100644
--- a/packages/twenty-sdk/vite.config.node.ts
+++ b/packages/twenty-sdk/vite.config.node.ts
@@ -5,6 +5,28 @@ import { defineConfig } from 'vite';
 
 import packageJson from './package.json';
 
+// Injected at the top of every ESM chunk so bundled CommonJS modules keep
+// working after rolldown inlines them into the `.mjs` output. They call
+// `require(...)` and read `__filename` / `__dirname` at runtime — none of which
+// exist in an ES module — so we recreate them from `import.meta.url`. Without
+// this the CLI crashes on startup ("Calling `require` for \"fs\" ...",
+// "__filename is not defined"). The CJS output already provides all three.
+// Aliased imports avoid colliding with bindings that already exist in a chunk.
+//
+// Note: __filename / __dirname resolve to the emitted chunk's own location
+// (dist/), not each inlined module's original node_modules path — so a bundled
+// dependency that reads __dirname to locate sibling files points at dist/.
+// esbuild's CJS-globals shim had the same limitation, so this is not a
+// regression; our own __dirname usage already targets dist/ intentionally.
+const esmNodeGlobalsBanner = [
+  "import { createRequire as __twentyCreateRequire } from 'node:module';",
+  "import { fileURLToPath as __twentyFileURLToPath } from 'node:url';",
+  "import { dirname as __twentyDirname } from 'node:path';",
+  'const require = __twentyCreateRequire(import.meta.url);',
+  'const __filename = __twentyFileURLToPath(import.meta.url);',
+  'const __dirname = __twentyDirname(__filename);',
+].join('\n');
+
 const copyCoverAssetsPlugin = () => ({
   name: 'copy-cover-assets',
   closeBundle() {
@@ -75,6 +97,7 @@ export default defineConfig(() => {
           {
             format: 'es' as const,
             entryFileNames: '[name].mjs',
+            banner: esmNodeGlobalsBanner,
           },
           {
             format: 'cjs' as const,