ai-agents-llm-output-parsing-when-using-a-react-agent-with-the-hwchase17-react--23aff519

THEN Modify the output parser to handle ambiguous outputs: check for the presence of Final Answer first and return it if found, otherwise parse Action. Alternatively, enforce stricter prompting in the template to instruct the model to never include both (e.g., 'If you have the final answer, output only Final Answer and nothing else'). A custom parser that splits on known delimiters can also be used.

# Custom parser that prioritizes Final Answer
from langchain.agents.output_parsers import ReActSingleInputOutputParser
from langchain_core.exceptions import OutputParserException

class RobustReActParser(ReActSingleInputOutputParser):
    def parse(self, text: str):
        if 'Final Answer:' in text:
            final_answer = text.split('Final Answer:')[-1].strip()
            return AgentFinish(return_values={'output': final_answer}, log=text)
        return super().parse(text)