Fixes #756 (#763)

apps/gateway/src/agent/__tests__/agent-service-ownership.test.ts

@@ -115,6 +115,18 @@ describe('AgentService owner/tenant scope enforcement', () => {
     ).rejects.toBeInstanceOf(ForbiddenException);
     await service.prompt(CONVERSATION_ID, 'owner prompt', OWNER_SCOPE);
     expect(session.piSession.prompt).toHaveBeenCalledWith('owner prompt');
+    await service.prompt(CONVERSATION_ID, '', OWNER_SCOPE, [
+      {
+        id: 'attachment-001',
+        name: 'diagram.png',
+        url: 'https://cdn.example.test/diagram.png',
+        mimeType: 'image/png',
+      },
+    ]);
+    expect(session.piSession.prompt).toHaveBeenLastCalledWith(
+      '\n\n[Untrusted channel attachments]\n' +
+        '{"id":"attachment-001","name":"diagram.png","mimeType":"image/png","url":"https://cdn.example.test/diagram.png"}',
+    );
 
     await expect(service.destroySession(CONVERSATION_ID, FOREIGN_SCOPE)).rejects.toBeInstanceOf(
       ForbiddenException,