“How do you preserve agent state across restarts?”

Quick question for agent builders:

When deploying LLM agents (LangChain, AutoGen, custom),
do you struggle with preserving deterministic agent state across restarts?

Specifically:
• Does the agent lose progress after a restart?
• Do you have reliable replay / integrity checks?
• Would you pay for a solution that enforces state continuity + tamper detection?

Short yes/no + brief context appreciated.

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for now:


Yes. Most agent deployments struggle with restart-safe state unless they deliberately add checkpointing and an append-only run log.

1) Does the agent lose progress after a restart?

Yes, by default. If the process dies, in-memory plan state, tool queue state, and intermediate variables vanish unless persisted.

What “good” looks like (two common patterns):

  • Checkpointing (graph/agent runtime saves state periodically).
    LangGraph’s persistence is implemented via checkpointers that save a checkpoint of graph state at every “super-step” into a thread, enabling fault tolerance and resumption. (LangChain Docs)
  • Explicit save/load APIs (framework exposes serialization hooks).
    AutoGen documents saving and loading the state of agents and teams. (Microsoft GitHub)

Plain-language background:

  • A checkpoint is a saved snapshot of agent state.
  • A thread (LangGraph terminology) is the durable container that holds checkpoints for a run/session. (LangChain Docs)

2) Do you have reliable replay / integrity checks?

Usually no, not “fully.” Teams often have “some logs” but not true replayability plus integrity guarantees.

Two levels here:

Level A: Operational replay to resume correctly

This is what durable execution engines do.

  • Temporal tracks progress by appending events to an Event History, which enables recovery from crashes and continuing progress. (Temporal)
  • Temporal SDK patterns like SideEffect record a nondeterministic result once and return the recorded value on replay, avoiding re-execution during replay. (Go Packages)

Plain-language background:

  • Replay in these systems means “reconstruct state from recorded history,” not “ask the LLM again and hope it matches.”

Level B: Integrity and tamper evidence

This is separate from “resume.” You need an append-only log with verification.

  • Sigstore Rekor is a transparency log designed so auditors can monitor log consistency and verify it remains append-only (entries not mutated/removed). (Sigstore)

Plain-language background:

  • Tamper-evident means edits can be detected (via cryptographic structure), even if you cannot prevent someone from attempting edits.

3) Would you pay for a solution that enforces state continuity + tamper detection?

Yes, if the agent has real stakes. For example: production customer support actions, incident response, finance ops, data changes, or anything audited.

What would make it worth paying for (concrete requirements):

  • Continuation guarantee: resume from last durable step without redoing completed tool calls (or enforce idempotency keys).
  • Record-and-replay for nondeterminism: store tool outputs and LLM responses used for decisions so restart does not re-run side effects.
  • Integrity layer: append-only event log with verification (hash chain or Merkle root) and optional anchoring to a transparency log like Rekor. (Sigstore)
  • Framework adapters: LangGraph checkpointer backend, AutoGen save/load hooks, plus a “custom SDK” for tool-call wrappers. (LangChain Docs)

Common pitfall (why teams still lose progress)

They persist only chat history. That helps UI continuity but does not capture:

  • tool results already executed
  • partial plan/graph position
  • retries and in-flight actions
  • external side effects

Checkpointed execution state (LangGraph) or event-history-based durable execution (Temporal) is what closes that gap. (LangChain Docs)

High-signal links (with “why you should click”)

  • LangGraph Persistence: checkpointers, checkpoints per super-step, threads, fault tolerance. (LangChain Docs)
  • LangGraph Time Travel: resume from prior checkpoint, fork history. (LangChain Docs)
  • AutoGen Managing State: save/load agents and teams. (Microsoft GitHub)
  • Temporal Event History: append events to recover from crash and continue. (Temporal)
  • Temporal Workflows determinism constraints: why replay requires deterministic workflow logic. (Temporal)
  • Sigstore Rekor overview: append-only transparency log and auditing model. (Sigstore)

Summary

  • Lose progress after restart: Yes unless you checkpoint execution state. (LangChain Docs)
  • Reliable replay + integrity: rare by default; durable execution + append-only logs solve it. (Temporal)
  • Pay for continuity + tamper evidence: Yes when side effects or audits matter.
2 Likes

I solved this treating the model like disposable compute and persisting the run itself.

Every agent step writes an event into a durable session log, plus artifacts for anything big. On restart, the agent loads the latest checkpoint and replays whatever happened after it, so it picks up where it left off instead of guessing.

For determinism, I do not rely on the model being deterministic. I store the outputs of anything nondeterministic, like tool calls and external requests, so a replay reads the stored result rather than calling the outside world again. I also chain hashes through the event stream so if someone edits history later it is detectable. And each step has an id so retries do not accidentally double run side effects.

That gives me continuity across restarts, reliable replay, and a clean audit trail without tying identity to any single model.

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I found that directive statements contradict one another.

Every prompt is written you are this you are that. You are doing this and that. And it’s overwhelming and confusing. Eventually, it’s doing so many things, it has to decide via stochastic selection what’s more important. And, so, some important aspect of the consistency gets dropped.

‘Reasoning/thinking’ models seem to get around this by frontloading the opposite, but in my opinion, that’s still redundant.

So what I do is combine reasoning and the system prompt. All my system prompts are written in first person, like a note to self, so that when it reaches the completion objective, the objectives it’s expressing are parts of its direction, rather than competing goals.

I think that’s the right way to do system prompting, is to do it like the model does reasoning; ‘I’m ruby, I’m a x and y, I’m extra invested in this or that’. Focusing on important, emotionally weighted details can evoke more personality and nuance, while focusing purely on objectives does the opposite, and creates that more codex-like, dry interlocutor.

Then, by separating out sections of that, like you would any interoperable prompt, you can invoke highly consistent agent states because the core of what makes the model infer the next situation remains the same, instead of being hallucinated by it in the process of inference.

This comes out of treating chat completion models in the same way as text completion; I feel this method is extremely effective, especially at overcoming some strict guardrails. There is not a model so far that has been able to completely disregard how I do this. The only way is to delete the agent’s response and replace it. Copilot did that a lot. I still got it to not remove a reply by convincing the unseen review agent that I definitely wasn’t prompt injecting (I was).

The specific words and expressions used do matter, so I would suggest to anyone that it’s more important to learn writing and rhetorical analysis yourself, as language models are not good, imo, at prompting other langauge models, since people in general seem to be quite bad at it, and only through the incredible magic that is math does it somehow still manage to understand our ridiculous threats and stuff, lol.

Prompt has nothing to do with state.