fix the issue

backend/api/services/agent_orchestrator.py

@@ -1884,6 +1884,16 @@ Answer:"""
             scratchpad_section = f"\n## Structured Notes\n{scratchpad_context}\n" if scratchpad_context else ""
             
             # Build prompt with Anthropic's structured format (XML-style sections)
+            # Pre-build optional web guidance section to avoid complex nested f-strings
+            if web_fallback_note:
+                web_guidance_section = (
+                    "<web_search_guidance>\n"
+                    f"{web_fallback_note.strip()}\n"
+                    "</web_search_guidance>\n\n"
+                )
+            else:
+                web_guidance_section = ""
+
             prompt = (
                 f"<system>\n"
                 f"You are an assistant helping tenant {req.tenant_id}. "
@@ -1897,7 +1907,7 @@ Answer:"""
                 f"The following details have been gathered from reliable sources:\n\n"
                 f"{data_section}\n"
                 f"</information_collected>\n\n"
-                f"{f'<web_search_guidance>\n{web_fallback_note.strip()}\n</web_search_guidance>\n\n' if web_fallback_note else ''}"
+                f"{web_guidance_section}"
                 f"<user_request>\n"
                 f"{req.message}\n"
                 f"</user_request>\n\n"