Cheat sheet

Graph engineering

From lesson 0013. Encode the valid paths. Leave holes where an agent may wander.

1. NodeDoes work. Code, one LLM call, or a full agent.
2. EdgeWhat happens next. Fixed or conditional.
3. StateThe ticket. A graph is a state machine.

Not

• Not the opposite of a loop — a loop is a tiny cyclic graph. Loop card.
• Not “always LangGraph.” Open research stays a harness. Harness card.
• Not a DAG religion. Production agents retry, ask, loop.
• Workflow vs agent is still the first split. That card.

Runkle & Chase: mix deterministic and agentic nodes. LangGraph is the runtime; Deep Agents is a harness on top. Whether the mix earned the floor is an eval. Evals card. When to climb to a graph at all: stack choice.