LangGraph router returning multiple values

[cocoza4]

According to https://langchain-ai.github.io/langgraph/how-tos/subgraphs-manage-state/#acting-as-the-entire-subgraph we can only route to only one path, my question is how can we implement a graph such that it supports a question that requires multiple routes e.g. both weather and other route.

For example with routes like this

class RouterState(MessagesState):
    route: Literal["weather", "sql", "other"]


class Router(TypedDict):
    route: Literal["weather", "sql", "other"]

Questions like what is the weather in SF and show me 3 countries with highest sales?

Thanks

[vbarda]

You would need to adjust the schema for the structured output to return multiple values and also set up conditional edges (i.e. route_after_prediction) to return multiple values (I am assuming in your case you would want to run the nodes you route to via multiple routes in parallel)

• For structured output w/ multiple values, you can do something like this:

class Router(TypedDict):
    route: list[Literal["weather", "sql", "other"]]

model = ChatOpenAI(model_name="gpt-4o-mini")
model.with_structured_output(Router).invoke("what is the weather in SF and show me 3 countries with highest sales?")
# {'route': ['weather', 'sql']}

• For conditional edges w/ multiple return values see this how-to guide: https://langchain-ai.github.io/langgraph/how-tos/branching/#conditional-branching

[cocoza4]

thank you very much. This answers my question.