most coding harnesses store the exact messages that have been sent to the llm and the messages items that have come back from the llm, not much else. Then, there is also a set of events/commands/etc that are in-memory only. Together they constitute the current state of the agent loop.

In Lightspeed, we store all of them as events, thus can always reconstruct the exact state of the loop (e.g. state of open tool calls, compaction decisions in-flight, etc). This makes it possible to run the agent in a durable workflow engine easily.