Source code for langchain.agents.conversational_chat.output_parser
from __future__ import annotations
from typing import Union
from langchain.agents import AgentOutputParser
from langchain.agents.conversational_chat.prompt import FORMAT_INSTRUCTIONS
from langchain.output_parsers.json import parse_json_markdown
from langchain.schema import AgentAction, AgentFinish, OutputParserException
# Define a class that parses output for conversational agents
[docs]class ConvoOutputParser(AgentOutputParser):
    """Output parser for the conversational agent."""
[docs]    def get_format_instructions(self) -> str:
        """Returns formatting instructions for the given output parser."""
        return FORMAT_INSTRUCTIONS
[docs]    def parse(self, text: str) -> Union[AgentAction, AgentFinish]:
        """Attempts to parse the given text into an AgentAction or AgentFinish.
        Raises:
             OutputParserException if parsing fails.
        """
        try:
            # Attempt to parse the text into a structured format (assumed to be JSON
            # stored as markdown)
            response = parse_json_markdown(text)
            # If the response contains an 'action' and 'action_input'
            if "action" in response and "action_input" in response:
                action, action_input = response["action"], response["action_input"]
                # If the action indicates a final answer, return an AgentFinish
                if action == "Final Answer":
                    return AgentFinish({"output": action_input}, text)
                else:
                    # Otherwise, return an AgentAction with the specified action and
                    # input
                    return AgentAction(action, action_input, text)
            else:
                # If the necessary keys aren't present in the response, raise an
                # exception
                raise OutputParserException(