langchain[patch]: runnable agent streaming param (#18761)

Usage:

```python
agent = RunnableAgent(runnable=runnable, .., stream_runnable=False)
```
or for convenience
```python
agent_executor = AgentExecutor(agent=agent, ..., stream_runnable=False)
```

libs/langchain/langchain/agents/agent.py

@@ -345,6 +345,14 @@ class RunnableAgent(BaseSingleActionAgent):
     """Runnable to call to get agent action."""
     input_keys_arg: List[str] = []
     return_keys_arg: List[str] = []
+    stream_runnable: bool = True
+    """Whether to stream from the runnable or not. 
+
+    If True then underlying LLM is invoked in a streaming fashion to make it possible 
+        to get access to the individual LLM tokens when using stream_log with the Agent 
+        Executor. If False then LLM is invoked in a non-streaming fashion and 
+        individual LLM tokens will not be available in stream_log.
+    """
 
     class Config:
         """Configuration for this pydantic object."""
@@ -378,17 +386,21 @@ class RunnableAgent(BaseSingleActionAgent):
             Action specifying what tool to use.
         """
         inputs = {**kwargs, **{"intermediate_steps": intermediate_steps}}
-        # Use streaming to make sure that the underlying LLM is invoked in a streaming
+        final_output: Any = None
+        if self.stream_runnable:
+            # Use streaming to make sure that the underlying LLM is invoked in a
+            # streaming
             # fashion to make it possible to get access to the individual LLM tokens
             # when using stream_log with the Agent Executor.
             # Because the response from the plan is not a generator, we need to
             # accumulate the output into final output and return that.
-        final_output: Any = None
             for chunk in self.runnable.stream(inputs, config={"callbacks": callbacks}):
                 if final_output is None:
                     final_output = chunk
                 else:
                     final_output += chunk
+        else:
+            final_output = self.runnable.invoke(inputs, config={"callbacks": callbacks})
 
         return final_output
 
@@ -414,7 +426,9 @@ class RunnableAgent(BaseSingleActionAgent):
         """
         inputs = {**kwargs, **{"intermediate_steps": intermediate_steps}}
         final_output: Any = None
-        # Use streaming to make sure that the underlying LLM is invoked in a streaming
+        if self.stream_runnable:
+            # Use streaming to make sure that the underlying LLM is invoked in a
+            # streaming
             # fashion to make it possible to get access to the individual LLM tokens
             # when using stream_log with the Agent Executor.
             # Because the response from the plan is not a generator, we need to
@@ -426,6 +440,10 @@ class RunnableAgent(BaseSingleActionAgent):
                     final_output = chunk
                 else:
                     final_output += chunk
+        else:
+            final_output = await self.runnable.ainvoke(
+                inputs, config={"callbacks": callbacks}
+            )
         return final_output
 
 
@@ -436,6 +454,14 @@ class RunnableMultiActionAgent(BaseMultiActionAgent):
     """Runnable to call to get agent actions."""
     input_keys_arg: List[str] = []
     return_keys_arg: List[str] = []
+    stream_runnable: bool = True
+    """Whether to stream from the runnable or not. 
+    
+    If True then underlying LLM is invoked in a streaming fashion to make it possible 
+        to get access to the individual LLM tokens when using stream_log with the Agent 
+        Executor. If False then LLM is invoked in a non-streaming fashion and 
+        individual LLM tokens will not be available in stream_log.
+    """
 
     class Config:
         """Configuration for this pydantic object."""
@@ -477,17 +503,21 @@ class RunnableMultiActionAgent(BaseMultiActionAgent):
             Action specifying what tool to use.
         """
         inputs = {**kwargs, **{"intermediate_steps": intermediate_steps}}
-        # Use streaming to make sure that the underlying LLM is invoked in a streaming
+        final_output: Any = None
+        if self.stream_runnable:
+            # Use streaming to make sure that the underlying LLM is invoked in a
+            # streaming
             # fashion to make it possible to get access to the individual LLM tokens
             # when using stream_log with the Agent Executor.
             # Because the response from the plan is not a generator, we need to
             # accumulate the output into final output and return that.
-        final_output: Any = None
             for chunk in self.runnable.stream(inputs, config={"callbacks": callbacks}):
                 if final_output is None:
                     final_output = chunk
                 else:
                     final_output += chunk
+        else:
+            final_output = self.runnable.invoke(inputs, config={"callbacks": callbacks})
 
         return final_output
 
@@ -512,12 +542,14 @@ class RunnableMultiActionAgent(BaseMultiActionAgent):
             Action specifying what tool to use.
         """
         inputs = {**kwargs, **{"intermediate_steps": intermediate_steps}}
-        # Use streaming to make sure that the underlying LLM is invoked in a streaming
+        final_output: Any = None
+        if self.stream_runnable:
+            # Use streaming to make sure that the underlying LLM is invoked in a
+            # streaming
             # fashion to make it possible to get access to the individual LLM tokens
             # when using stream_log with the Agent Executor.
             # Because the response from the plan is not a generator, we need to
             # accumulate the output into final output and return that.
-        final_output: Any = None
             async for chunk in self.runnable.astream(
                 inputs, config={"callbacks": callbacks}
             ):
@@ -525,6 +557,10 @@ class RunnableMultiActionAgent(BaseMultiActionAgent):
                     final_output = chunk
                 else:
                     final_output += chunk
+        else:
+            final_output = await self.runnable.ainvoke(
+                inputs, config={"callbacks": callbacks}
+            )
 
         return final_output
 
@@ -977,10 +1013,15 @@ class AgentExecutor(Chain):
             else:
                 multi_action = output_type == Union[List[AgentAction], AgentFinish]
 
+            stream_runnable = values.pop("stream_runnable", True)
             if multi_action:
-                values["agent"] = RunnableMultiActionAgent(runnable=agent)
+                values["agent"] = RunnableMultiActionAgent(
+                    runnable=agent, stream_runnable=stream_runnable
+                )
             else:
-                values["agent"] = RunnableAgent(runnable=agent)
+                values["agent"] = RunnableAgent(
+                    runnable=agent, stream_runnable=stream_runnable
+                )
         return values
 
     def save(self, file_path: Union[Path, str]) -> None: