JSON errors in non-interactive auth validation (#8373)

integration-tests/json-output.test.ts

@@ -34,4 +34,38 @@ describe('JSON output', () => {
     expect(parsed).toHaveProperty('stats');
     expect(typeof parsed.stats).toBe('object');
   });
+
+  it('should return a JSON error for enforced auth mismatch before running', async () => {
+    process.env['GOOGLE_GENAI_USE_GCA'] = 'true';
+    await rig.setup('json-output-auth-mismatch', {
+      settings: {
+        security: { auth: { enforcedType: 'gemini-api-key' } },
+      },
+    });
+
+    let thrown: Error | undefined;
+    try {
+      await rig.run('Hello', '--output-format', 'json');
+      expect.fail('Expected process to exit with error');
+    } catch (e) {
+      thrown = e as Error;
+    } finally {
+      delete process.env['GOOGLE_GENAI_USE_GCA'];
+    }
+
+    expect(thrown).toBeDefined();
+    const message = (thrown as Error).message;
+    const jsonStart = message.indexOf('{');
+    expect(jsonStart).toBeGreaterThan(-1);
+    const payload = JSON.parse(message.slice(jsonStart));
+    expect(payload.error).toBeDefined();
+    expect(payload.error.type).toBe('Error');
+    expect(payload.error.code).toBe(1);
+    expect(payload.error.message).toContain(
+      'configured auth type is gemini-api-key',
+    );
+    expect(payload.error.message).toContain(
+      'current auth type is oauth-personal',
+    );
+  });
 });