Overview
Memory, resumability and time-travel debugging.
Why it matters
Without a checkpointer, your agent forgets everything on every request. With one, it gets multi-turn memory and crash-recovery for free.
Where this sits in the stack
Checkpointers and persistence is one of the load-bearing decisions in a KG/RAG/agent system: choices made here propagate to retrieval quality, agent reliability, cost per query, and the on-call burden of whoever ships it. Teams that name this trade-off explicitly ship faster than teams that leave it implicit.