From 5ee3cb9ae68ac8a58997b37cfd0989ebdc182df2 Mon Sep 17 00:00:00 2001
From: Anton Nakonechny <anton.nakonechny@gmail.com>
Date: Sun, 21 Jun 2026 16:55:12 +0200
Subject: [PATCH] Fix response text extraction and update to latest Claude
 model

- Add _extract_text() helper to safely extract text from Claude responses, handling edge cases where content may be empty or contain non-text blocks
- Update ANTHROPIC_MODEL from 4-20250514 to latest stable 4.6

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
---
 backend/ai_generator.py | 19 ++++++++++++++++---
 backend/config.py       |  2 +-
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/backend/ai_generator.py b/backend/ai_generator.py
index 0363ca90c..69f5403fd 100644
--- a/backend/ai_generator.py
+++ b/backend/ai_generator.py
@@ -82,9 +82,22 @@ def generate_response(self, query: str,
         # Handle tool execution if needed
         if response.stop_reason == "tool_use" and tool_manager:
             return self._handle_tool_execution(response, api_params, tool_manager)
-        
+
         # Return direct response
-        return response.content[0].text
+        return self._extract_text(response)
+
+    @staticmethod
+    def _extract_text(response) -> str:
+        """Safely extract text from a Claude response.
+
+        The model can return an empty content list (e.g. an end_turn with no
+        text) or lead with a non-text block. Guard against both rather than
+        assuming content[0] is always a text block.
+        """
+        for block in response.content:
+            if getattr(block, "type", None) == "text":
+                return block.text
+        return ""
     
     def _handle_tool_execution(self, initial_response, base_params: Dict[str, Any], tool_manager):
         """
@@ -132,4 +145,4 @@ def _handle_tool_execution(self, initial_response, base_params: Dict[str, Any],
         
         # Get final response
         final_response = self.client.messages.create(**final_params)
-        return final_response.content[0].text
\ No newline at end of file
+        return self._extract_text(final_response)
\ No newline at end of file
diff --git a/backend/config.py b/backend/config.py
index d9f6392ef..a3416c898 100644
--- a/backend/config.py
+++ b/backend/config.py
@@ -10,7 +10,7 @@ class Config:
     """Configuration settings for the RAG system"""
     # Anthropic API settings
     ANTHROPIC_API_KEY: str = os.getenv("ANTHROPIC_API_KEY", "")
-    ANTHROPIC_MODEL: str = "claude-sonnet-4-20250514"
+    ANTHROPIC_MODEL: str = "claude-sonnet-4-6"
     
     # Embedding model settings
     EMBEDDING_MODEL: str = "all-MiniLM-L6-v2"