fix(cli): single trailing newline on css-tailwind export

packages/cli/src/commands/export.ts

@@ -62,7 +62,8 @@ export default defineCommand({
         return;
       }
 
-      console.log(serializeTailwindV4(result.data.theme));
+      // serializeTailwindV4 already ends with a single trailing newline; avoid console.log's extra newline.
+      process.stdout.write(serializeTailwindV4(result.data.theme));
     } else if (format === 'json-tailwind' || format === 'tailwind') {
       const handler = new TailwindEmitterHandler();
       const result = handler.execute(report.designSystem);

packages/cli/src/linter/tailwind/v4/serialize.test.ts

@@ -93,4 +93,10 @@ describe('serializeToCss', () => {
     const out = serializeToCss(data);
     expect(out).toContain('--font-body: "Google Sans Display";');
   });
+
+  it('ends with exactly one trailing newline (for stdout.write export path)', () => {
+    const out = serializeToCss({ colors: { primary: '#000000', 'on-primary': '#ffffff' } });
+    expect(out.endsWith('\n')).toBe(true);
+    expect(out.endsWith('\n\n')).toBe(false);
+  });
 });

packages/cli/src/utils.ts

@@ -31,13 +31,16 @@ export async function readInput(filePath: string): Promise<string> {
   try {
     return readFileSync(filePath, 'utf-8');
   } catch (error) {
+    const message = error instanceof Error ? error.message : String(error);
+    const hint = message.includes('ENOENT')
+      ? `Design file not found: ${filePath}. Create a DESIGN.md or pass an existing path.`
+      : message;
     console.error(JSON.stringify({
       error: 'FILE_READ_ERROR',
-      message: error instanceof Error ? error.message : String(error),
+      message: hint,
       path: filePath,
     }));
-    process.exitCode = 2;
-    throw error; // bubbles up, but process will exit with code 2 if uncaught
+    process.exit(2);
   }
 }