chore(langchain): simplify create_agent so mypy can infer typing

[cbornet]

CompiledStateGraph's StateT and OutputT are useless for the caller of create_agent.
So we can replace them by Any and this make mypy able to correctly infer the typing.

NB: it would be nice to change the signature of CompiledStateGraph to a Generic[ContextT, InputT] in LangGraph since it does not use StateT and OutputT.

[sydney-runkle]

NB: it would be nice to change the signature of CompiledStateGraph to a Generic[ContextT, InputT] in LangGraph since it does not use StateT and OutputT.

I don't think this makes sense, we do use OutputT on invocation results, and StateT is helpful when defining node functions...

edit - I see what you mean re caller of create_agent, but not for OutputT...

[sydney-runkle]

Should we go ahead and make the input and output types public here?

[cbornet]

Should we go ahead and make the input and output types public here?

Done. This also removed 2 ruff warnings 😃

[sydney-runkle]

Suggested change

	) -> CompiledStateGraph[Any, ContextT, InputAgentState, Any]:
	) -> CompiledStateGraph[AgentState[ResponseT], ContextT, InputAgentState, OutputAgentState[ResponseT]]

Does this hurt?

[cbornet]

Does this hurt?

Yes, because if we do that, mypy can't infer the type of the create_agent call and the caller has to define it explicitly. It's the goal of this PR to remove these types so that mypy can do the inference.
Those generics (StateT and OutputT) are not used anyway in CompiledStateGraph.