Add support for multiline answers in ReActOutputParser (Fixes #7690) (#…

…8029)

CHANGELOG.md

@@ -7,6 +7,7 @@
 - Enable `codespell` for markdown docs (#7972)
 
 ### Bug Fixes / Nits
+- Parse multi-line outputs in react agent answers (#8029)
 - Add properly named kwargs to keyword `as_retriever` calls (#8011)
 
 ## [0.8.41] - 2023-10-07

llama_index/agent/react/output_parser.py

@@ -29,7 +29,7 @@ def extract_tool_use(input_text: str) -> Tuple[str, str, str]:
 
 
 def extract_final_response(input_text: str) -> Tuple[str, str]:
-    pattern = r"\s*Thought:(.*?)Answer:(.*?)(?:\n|$)"
+    pattern = r"\s*Thought:(.*?)Answer:(.*?)(?:$)"
 
     match = re.search(pattern, input_text, re.DOTALL)
     if not match:

tests/agent/react/test_react_output_parser.py

@@ -43,3 +43,25 @@ def test_extract_final_response() -> None:
     thought, answer = extract_final_response(mock_input_text)
     assert thought == expected_thought
     assert answer == "2"
+
+
+def test_extract_final_response_multiline_answer() -> None:
+    mock_input_text = """\
+Thought: I have enough information to answer the question without using any more tools.
+Answer: Here is the answer:
+
+This is the second line.
+"""
+
+    expected_thought = (
+        "I have enough information to answer the question "
+        "without using any more tools."
+    )
+    thought, answer = extract_final_response(mock_input_text)
+    assert thought == expected_thought
+    assert (
+        answer
+        == """Here is the answer:
+
+This is the second line."""
+    )