From eb9b334a6b78af0d56b0e01fe6a0e36a7dba91b8 Mon Sep 17 00:00:00 2001
From: Tal <73430602+treisfeld@users.noreply.github.com>
Date: Fri, 12 Jan 2024 07:52:36 +0200
Subject: [PATCH] Enable customizing the output parser of
 `OpenAIFunctionsAgent` (#15827)

- **Description:** This PR defines the output parser of
OpenAIFunctionsAgent as an attribute, enabling customization and
subclassing of the parser logic.
- **Issue:** Subclassing is currently impossible as the
`OpenAIFunctionsAgentOutputParser` class is hard coded into the `plan`
and `aplan` methods
  - **Dependencies:** None

<!-- Thank you for contributing to LangChain!

Please title your PR "<package>: <description>", where <package> is
whichever of langchain, community, core, experimental, etc. is being
modified.

Replace this entire comment with:
  - **Description:** a description of the change,
  - **Issue:** the issue # it fixes if applicable,
  - **Dependencies:** any dependencies required for this change,
- **Twitter handle:** we announce bigger features on Twitter. If your PR
gets announced, and you'd like a mention, we'll gladly shout you out!

Please make sure your PR is passing linting and testing before
submitting. Run `make format`, `make lint` and `make test` from the root
of the package you've modified to check this locally.

See contribution guidelines for more information on how to write/run
tests, lint, etc: https://python.langchain.com/docs/contributing/

If you're adding a new integration, please include:
1. a test for the integration, preferably unit tests that do not rely on
network access,
2. an example notebook showing its use. It lives in
`docs/docs/integrations` directory.

If no one reviews your PR within a few days, please @-mention one of
@baskaryan, @eyurtsev, @hwchase17.
 -->

---------

Co-authored-by: Harrison Chase <hw.chase.17@gmail.com>
---
 .../langchain/agents/openai_functions_agent/base.py | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/libs/langchain/langchain/agents/openai_functions_agent/base.py b/libs/langchain/langchain/agents/openai_functions_agent/base.py
index 9e6c6e0cfd..f388f5cae2 100644
--- a/libs/langchain/langchain/agents/openai_functions_agent/base.py
+++ b/libs/langchain/langchain/agents/openai_functions_agent/base.py
@@ -1,5 +1,5 @@
 """Module implements an agent that uses OpenAI's APIs function enabled API."""
-from typing import Any, List, Optional, Sequence, Tuple, Union
+from typing import Any, List, Optional, Sequence, Tuple, Type, Union
 
 from langchain_community.tools.convert_to_openai import format_tool_to_openai_function
 from langchain_core._api import deprecated
@@ -47,6 +47,9 @@ class OpenAIFunctionsAgent(BaseSingleActionAgent):
     llm: BaseLanguageModel
     tools: Sequence[BaseTool]
     prompt: BasePromptTemplate
+    output_parser: Type[
+        OpenAIFunctionsAgentOutputParser
+    ] = OpenAIFunctionsAgentOutputParser
 
     def get_allowed_tools(self) -> List[str]:
         """Get allowed tools."""
@@ -105,9 +108,7 @@ class OpenAIFunctionsAgent(BaseSingleActionAgent):
                 messages,
                 callbacks=callbacks,
             )
-        agent_decision = OpenAIFunctionsAgentOutputParser._parse_ai_message(
-            predicted_message
-        )
+        agent_decision = self.output_parser._parse_ai_message(predicted_message)
         return agent_decision
 
     async def aplan(
@@ -136,9 +137,7 @@ class OpenAIFunctionsAgent(BaseSingleActionAgent):
         predicted_message = await self.llm.apredict_messages(
             messages, functions=self.functions, callbacks=callbacks
         )
-        agent_decision = OpenAIFunctionsAgentOutputParser._parse_ai_message(
-            predicted_message
-        )
+        agent_decision = self.output_parser._parse_ai_message(predicted_message)
         return agent_decision
 
     def return_stopped_response(