langchain: Standardize output_parser.py across all agent types for custom FORMAT_INSTRUCTIONS

libs/langchain/langchain/agents/chat/output_parser.py

@@ -14,11 +14,15 @@
 class ChatOutputParser(AgentOutputParser):
     """Output parser for the chat agent."""
 
+    format_instructions: str = FORMAT_INSTRUCTIONS
+    """Default formatting instructions"""
+
     pattern = re.compile(r"^.*?`{3}(?:json)?\n(.*?)`{3}.*?$", re.DOTALL)
     """Regex pattern to parse the output."""
 
     def get_format_instructions(self) -> str:
-        return FORMAT_INSTRUCTIONS
+        """Returns formatting instructions for the given output parser."""
+        return self.format_instructions
 
     def parse(self, text: str) -> Union[AgentAction, AgentFinish]:
         includes_answer = FINAL_ANSWER_ACTION in text

libs/langchain/langchain/agents/conversational/output_parser.py

@@ -14,8 +14,12 @@ class ConvoOutputParser(AgentOutputParser):
     ai_prefix: str = "AI"
     """Prefix to use before AI output."""
 
+    format_instructions: str = FORMAT_INSTRUCTIONS
+    """Default formatting instructions"""
+
     def get_format_instructions(self) -> str:
-        return FORMAT_INSTRUCTIONS
+        """Returns formatting instructions for the given output parser."""
+        return self.format_instructions
 
     def parse(self, text: str) -> Union[AgentAction, AgentFinish]:
         if f"{self.ai_prefix}:" in text:

libs/langchain/langchain/agents/conversational_chat/output_parser.py

@@ -15,6 +15,7 @@ class ConvoOutputParser(AgentOutputParser):
     """Output parser for the conversational agent."""
 
     format_instructions: str = FORMAT_INSTRUCTIONS
+    """Default formatting instructions"""
 
     def get_format_instructions(self) -> str:
         """Returns formatting instructions for the given output parser."""

libs/langchain/langchain/agents/mrkl/output_parser.py

@@ -22,8 +22,12 @@
 class MRKLOutputParser(AgentOutputParser):
     """MRKL Output parser for the chat agent."""
 
+    format_instructions: str = FORMAT_INSTRUCTIONS
+    """Default formatting instructions"""
+
     def get_format_instructions(self) -> str:
-        return FORMAT_INSTRUCTIONS
+        """Returns formatting instructions for the given output parser."""
+        return self.format_instructions
 
     def parse(self, text: str) -> Union[AgentAction, AgentFinish]:
         includes_answer = FINAL_ANSWER_ACTION in text

libs/langchain/langchain/agents/structured_chat/output_parser.py

@@ -20,10 +20,15 @@
 class StructuredChatOutputParser(AgentOutputParser):
     """Output parser for the structured chat agent."""
 
+    format_instructions: str = FORMAT_INSTRUCTIONS
+    """Default formatting instructions"""
+
     pattern = re.compile(r"```(?:json\s+)?(\W.*?)```", re.DOTALL)
+    """Regex pattern to parse the output."""
 
     def get_format_instructions(self) -> str:
-        return FORMAT_INSTRUCTIONS
+        """Returns formatting instructions for the given output parser."""
+        return self.format_instructions
 
     def parse(self, text: str) -> Union[AgentAction, AgentFinish]:
         try: