diff --git a/x-pack/test/observability_ai_assistant_api_integration/common/config.ts b/x-pack/test/observability_ai_assistant_api_integration/common/config.ts
index 455004e5339fd..6505ad3e94d64 100644
--- a/x-pack/test/observability_ai_assistant_api_integration/common/config.ts
+++ b/x-pack/test/observability_ai_assistant_api_integration/common/config.ts
@@ -33,6 +33,16 @@ export type ObservabilityAIAssistantAPIClient = Awaited<
 
 export type ObservabilityAIAssistantServices = Awaited<ReturnType<CreateTestConfig>>['services'];
 
+export class ForbiddenApiError extends Error {
+  status: number;
+
+  constructor(message: string = 'Forbidden') {
+    super(message);
+    this.name = 'ForbiddenApiError';
+    this.status = 403;
+  }
+}
+
 export function createObservabilityAIAssistantAPIConfig({
   config,
   license,
diff --git a/x-pack/test/observability_ai_assistant_api_integration/tests/chat/chat.spec.ts b/x-pack/test/observability_ai_assistant_api_integration/tests/chat/chat.spec.ts
index c0a3da475e0ca..cedd4c286dc1a 100644
--- a/x-pack/test/observability_ai_assistant_api_integration/tests/chat/chat.spec.ts
+++ b/x-pack/test/observability_ai_assistant_api_integration/tests/chat/chat.spec.ts
@@ -11,6 +11,7 @@ import { PassThrough } from 'stream';
 import { createLlmProxy, LlmProxy } from '../../common/create_llm_proxy';
 import { FtrProviderContext } from '../../common/ftr_provider_context';
 import { createProxyActionConnector, deleteActionConnector } from '../../common/action_connectors';
+import { ForbiddenApiError } from '../../common/config';
 
 export default function ApiTest({ getService }: FtrProviderContext) {
   const supertest = getService('supertest');
@@ -200,6 +201,7 @@ export default function ApiTest({ getService }: FtrProviderContext) {
               },
             },
           });
+          throw new ForbiddenApiError('Expected unauthorizedUser() to throw a 403 Forbidden error');
         } catch (e) {
           expect(e.status).to.be(403);
         }
diff --git a/x-pack/test/observability_ai_assistant_api_integration/tests/complete/complete.spec.ts b/x-pack/test/observability_ai_assistant_api_integration/tests/complete/complete.spec.ts
index 5e59eed3a8c2b..86e357e2e7760 100644
--- a/x-pack/test/observability_ai_assistant_api_integration/tests/complete/complete.spec.ts
+++ b/x-pack/test/observability_ai_assistant_api_integration/tests/complete/complete.spec.ts
@@ -32,6 +32,7 @@ import {
   getConversationUpdatedEvent,
 } from '../conversations/helpers';
 import { createProxyActionConnector, deleteActionConnector } from '../../common/action_connectors';
+import { ForbiddenApiError } from '../../common/config';
 
 export default function ApiTest({ getService }: FtrProviderContext) {
   const supertest = getService('supertest');
@@ -502,6 +503,7 @@ export default function ApiTest({ getService }: FtrProviderContext) {
               },
             },
           });
+          throw new ForbiddenApiError('Expected unauthorizedUser() to throw a 403 Forbidden error');
         } catch (e) {
           expect(e.status).to.be(403);
         }
diff --git a/x-pack/test/observability_ai_assistant_api_integration/tests/connectors/connectors.spec.ts b/x-pack/test/observability_ai_assistant_api_integration/tests/connectors/connectors.spec.ts
index 84b044d4b84aa..42e1f8751719e 100644
--- a/x-pack/test/observability_ai_assistant_api_integration/tests/connectors/connectors.spec.ts
+++ b/x-pack/test/observability_ai_assistant_api_integration/tests/connectors/connectors.spec.ts
@@ -9,6 +9,7 @@ import expect from '@kbn/expect';
 import type { Agent as SuperTestAgent } from 'supertest';
 import { FtrProviderContext } from '../../common/ftr_provider_context';
 import { createProxyActionConnector, deleteActionConnector } from '../../common/action_connectors';
+import { ForbiddenApiError } from '../../common/config';
 
 export default function ApiTest({ getService }: FtrProviderContext) {
   const observabilityAIAssistantAPIClient = getService('observabilityAIAssistantAPIClient');
@@ -60,6 +61,7 @@ export default function ApiTest({ getService }: FtrProviderContext) {
           await observabilityAIAssistantAPIClient.unauthorizedUser({
             endpoint: `GET ${CONNECTOR_API_URL}`,
           });
+          throw new ForbiddenApiError('Expected unauthorizedUser() to throw a 403 Forbidden error');
         } catch (e) {
           expect(e.status).to.be(403);
         }
diff --git a/x-pack/test/observability_ai_assistant_api_integration/tests/conversations/conversations.spec.ts b/x-pack/test/observability_ai_assistant_api_integration/tests/conversations/conversations.spec.ts
index 3db3be8ec6713..bb85e99b99500 100644
--- a/x-pack/test/observability_ai_assistant_api_integration/tests/conversations/conversations.spec.ts
+++ b/x-pack/test/observability_ai_assistant_api_integration/tests/conversations/conversations.spec.ts
@@ -14,6 +14,7 @@ import {
 } from '@kbn/observability-ai-assistant-plugin/common/types';
 import type { FtrProviderContext } from '../../common/ftr_provider_context';
 import type { SupertestReturnType } from '../../common/observability_ai_assistant_api_client';
+import { ForbiddenApiError } from '../../common/config';
 
 export default function ApiTest({ getService }: FtrProviderContext) {
   const observabilityAIAssistantAPIClient = getService('observabilityAIAssistantAPIClient');
@@ -292,6 +293,9 @@ export default function ApiTest({ getService }: FtrProviderContext) {
                 },
               },
             });
+            throw new ForbiddenApiError(
+              'Expected unauthorizedUser() to throw a 403 Forbidden error'
+            );
           } catch (e) {
             expect(e.status).to.be(403);
           }
@@ -302,6 +306,9 @@ export default function ApiTest({ getService }: FtrProviderContext) {
             await observabilityAIAssistantAPIClient.unauthorizedUser({
               endpoint: 'POST /internal/observability_ai_assistant/conversations',
             });
+            throw new ForbiddenApiError(
+              'Expected unauthorizedUser() to throw a 403 Forbidden error'
+            );
           } catch (e) {
             expect(e.status).to.be(403);
           }
@@ -322,6 +329,9 @@ export default function ApiTest({ getService }: FtrProviderContext) {
                 },
               },
             });
+            throw new ForbiddenApiError(
+              'Expected unauthorizedUser() to throw a 403 Forbidden error'
+            );
           } catch (e) {
             expect(e.status).to.be(403);
           }
@@ -337,6 +347,9 @@ export default function ApiTest({ getService }: FtrProviderContext) {
                 },
               },
             });
+            throw new ForbiddenApiError(
+              'Expected unauthorizedUser() to throw a 403 Forbidden error'
+            );
           } catch (e) {
             expect(e.status).to.be(403);
           }
@@ -352,6 +365,9 @@ export default function ApiTest({ getService }: FtrProviderContext) {
                 },
               },
             });
+            throw new ForbiddenApiError(
+              'Expected unauthorizedUser() to throw a 403 Forbidden error'
+            );
           } catch (e) {
             expect(e.status).to.be(403);
           }
diff --git a/x-pack/test/observability_ai_assistant_api_integration/tests/knowledge_base/knowledge_base.spec.ts b/x-pack/test/observability_ai_assistant_api_integration/tests/knowledge_base/knowledge_base.spec.ts
index 73d53ffa6d1f4..9d80db3baeae6 100644
--- a/x-pack/test/observability_ai_assistant_api_integration/tests/knowledge_base/knowledge_base.spec.ts
+++ b/x-pack/test/observability_ai_assistant_api_integration/tests/knowledge_base/knowledge_base.spec.ts
@@ -15,6 +15,7 @@ import {
   deleteInferenceEndpoint,
   deleteKnowledgeBaseModel,
 } from './helpers';
+import { ForbiddenApiError } from '../../common/config';
 
 export default function ApiTest({ getService }: FtrProviderContext) {
   const ml = getService('ml');
@@ -225,6 +226,9 @@ export default function ApiTest({ getService }: FtrProviderContext) {
                 },
               },
             });
+            throw new ForbiddenApiError(
+              'Expected unauthorizedUser() to throw a 403 Forbidden error'
+            );
           } catch (e) {
             expect(e.status).to.be(403);
           }
@@ -238,6 +242,9 @@ export default function ApiTest({ getService }: FtrProviderContext) {
                 query: { query: '', sortBy: 'title', sortDirection: 'asc' },
               },
             });
+            throw new ForbiddenApiError(
+              'Expected unauthorizedUser() to throw a 403 Forbidden error'
+            );
           } catch (e) {
             expect(e.status).to.be(403);
           }
@@ -251,6 +258,9 @@ export default function ApiTest({ getService }: FtrProviderContext) {
                 path: { entryId: 'my-doc-id-1' },
               },
             });
+            throw new ForbiddenApiError(
+              'Expected unauthorizedUser() to throw a 403 Forbidden error'
+            );
           } catch (e) {
             expect(e.status).to.be(403);
           }
diff --git a/x-pack/test/observability_ai_assistant_api_integration/tests/knowledge_base/knowledge_base_setup.spec.ts b/x-pack/test/observability_ai_assistant_api_integration/tests/knowledge_base/knowledge_base_setup.spec.ts
index 8220c4edc9c63..0d7625bb63ed3 100644
--- a/x-pack/test/observability_ai_assistant_api_integration/tests/knowledge_base/knowledge_base_setup.spec.ts
+++ b/x-pack/test/observability_ai_assistant_api_integration/tests/knowledge_base/knowledge_base_setup.spec.ts
@@ -13,6 +13,7 @@ import {
   TINY_ELSER,
   deleteInferenceEndpoint,
 } from './helpers';
+import { ForbiddenApiError } from '../../common/config';
 
 export default function ApiTest({ getService }: FtrProviderContext) {
   const ml = getService('ml');
@@ -74,6 +75,7 @@ export default function ApiTest({ getService }: FtrProviderContext) {
               },
             },
           });
+          throw new ForbiddenApiError('Expected unauthorizedUser() to throw a 403 Forbidden error');
         } catch (e) {
           expect(e.status).to.be(403);
         }
diff --git a/x-pack/test/observability_ai_assistant_api_integration/tests/knowledge_base/knowledge_base_status.spec.ts b/x-pack/test/observability_ai_assistant_api_integration/tests/knowledge_base/knowledge_base_status.spec.ts
index 7ff78751d474f..3f66931ca0719 100644
--- a/x-pack/test/observability_ai_assistant_api_integration/tests/knowledge_base/knowledge_base_status.spec.ts
+++ b/x-pack/test/observability_ai_assistant_api_integration/tests/knowledge_base/knowledge_base_status.spec.ts
@@ -13,6 +13,7 @@ import {
   TINY_ELSER,
   deleteInferenceEndpoint,
 } from './helpers';
+import { ForbiddenApiError } from '../../common/config';
 
 export default function ApiTest({ getService }: FtrProviderContext) {
   const ml = getService('ml');
@@ -89,6 +90,7 @@ export default function ApiTest({ getService }: FtrProviderContext) {
           await observabilityAIAssistantAPIClient.unauthorizedUser({
             endpoint: `GET ${KNOWLEDGE_BASE_STATUS_API_URL}`,
           });
+          throw new ForbiddenApiError('Expected unauthorizedUser() to throw a 403 Forbidden error');
         } catch (e) {
           expect(e.status).to.be(403);
         }
diff --git a/x-pack/test/observability_ai_assistant_api_integration/tests/knowledge_base/knowledge_base_user_instructions.spec.ts b/x-pack/test/observability_ai_assistant_api_integration/tests/knowledge_base/knowledge_base_user_instructions.spec.ts
index dbb3fa1fada0a..d5022a052d781 100644
--- a/x-pack/test/observability_ai_assistant_api_integration/tests/knowledge_base/knowledge_base_user_instructions.spec.ts
+++ b/x-pack/test/observability_ai_assistant_api_integration/tests/knowledge_base/knowledge_base_user_instructions.spec.ts
@@ -23,6 +23,7 @@ import { getConversationCreatedEvent } from '../conversations/helpers';
 import { LlmProxy, createLlmProxy } from '../../common/create_llm_proxy';
 import { createProxyActionConnector, deleteActionConnector } from '../../common/action_connectors';
 import { User } from '../../common/users/users';
+import { ForbiddenApiError } from '../../common/config';
 
 export default function ApiTest({ getService }: FtrProviderContext) {
   const observabilityAIAssistantAPIClient = getService('observabilityAIAssistantAPIClient');
@@ -377,6 +378,9 @@ export default function ApiTest({ getService }: FtrProviderContext) {
                 },
               },
             });
+            throw new ForbiddenApiError(
+              'Expected unauthorizedUser() to throw a 403 Forbidden error'
+            );
           } catch (e) {
             expect(e.status).to.be(403);
           }
@@ -387,6 +391,9 @@ export default function ApiTest({ getService }: FtrProviderContext) {
             await observabilityAIAssistantAPIClient.unauthorizedUser({
               endpoint: 'GET /internal/observability_ai_assistant/kb/user_instructions',
             });
+            throw new ForbiddenApiError(
+              'Expected unauthorizedUser() to throw a 403 Forbidden error'
+            );
           } catch (e) {
             expect(e.status).to.be(403);
           }