Source code for langchain.agents.output_parsers.json
from __future__ import annotations
import logging
from typing import Union
from langchain_core.agents import AgentAction, AgentFinish
from langchain_core.exceptions import OutputParserException
from langchain_core.output_parsers.json import parse_json_markdown
from langchain.agents.agent import AgentOutputParser
logger = logging.getLogger(__name__)
[docs]class JSONAgentOutputParser(AgentOutputParser):
"""Parses tool invocations and final answers in JSON format.
Expects output to be in one of two formats.
If the output signals that an action should be taken,
should be in the below format. This will result in an AgentAction
being returned.
```
{
"action": "search",
"action_input": "2+2"
}
```
If the output signals that a final answer should be given,
should be in the below format. This will result in an AgentFinish
being returned.
```
{
"action": "Final Answer",
"action_input": "4"
}
```
"""
[docs] def parse(self, text: str) -> Union[AgentAction, AgentFinish]:
try:
response = parse_json_markdown(text)
if isinstance(response, list):
# gpt turbo frequently ignores the directive to emit a single action
logger.warning("Got multiple action responses: %s", response)
response = response[0]
if response["action"] == "Final Answer":
return AgentFinish({"output": response["action_input"]}, text)
else:
return AgentAction(
response["action"], response.get("action_input", {}), text
)
except Exception as e:
raise OutputParserException(f"Could not parse LLM output: {text}") from e
@property
def _type(self) -> str:
return "json-agent"