LangGraph Checkpointing (Python) Overview A chat agent that "keeps introducing itself" is almost always P16. The caller invokes without passing — LangGraph's checkpointer silently spawns a fresh state per call. No error, no warning, no log line. The user sees it; the code does not. That is one of five separate checkpointing pitfalls this skill covers: - P16 — missing silently resets memory - P17 — raises when state holds non-JSON values ( , , custom classes) — and it raises at the interrupt boundary , not when the bad value was first assigned, so the traceback points at the wrong line - P20 —…