Each page is a focused take on one idea. Read top-to-bottom for a tour of the framework, or jump to whichever concept you need.
- State and reducers: typed state, per-field merge policies, what makes nodes safe to write.
- Graphs: nodes, edges, build, invoke: the four moves you make to turn a state schema into a runnable pipeline.
- Composition: conditional edges, subgraphs, projection: routing decisions, encapsulated sub-pipelines, the parent ↔ subgraph data seam.
- Fan-out: running the same subgraph many times in parallel, results merged back deterministically.
- LLMs: how LLM calls fit into nodes, structured output, routing on parsed fields, errors at the LLM boundary.
- Observability: node-boundary hooks, OTel mapping, log correlation.
- Checkpointing: save state at each node boundary, resume from a prior point.
If you're brand-new, Quickstart is the faster entry; under a minute to a running graph. Come back here when you want to know why things are shaped the way they are.