State, Memory, and Checkpoints

State, Memory, and Checkpoints

Key jargon

Term Plain-language meaning
State The authoritative data describing the current workflow position and values.
Memory Information retained for later use, often selected or summarized from prior interactions.
Checkpoint A durable snapshot from which execution can resume.
Event log An append-only sequence of facts describing state transitions.

Key concepts

Concept map

flowchart LR
    A["Observe event"] --> B["Persist state transition"]
    B --> C["Create checkpoint"]
    C --> D["Resume with selected memory"]
Kind Example Lifetime
Turn context Current user message One invocation
Run state Completed steps and pending approval One workflow run
Artifact Draft, report, code patch, dataset Project-defined
User memory Preference explicitly saved for future use Until expiry/deletion
Knowledge memory Curated facts with source and version Until superseded
Model weights Learned behavior from training Model release

Do not call the conversation window “memory” without qualification. Durable memory needs consent, provenance, namespace, conflict handling, retention, and deletion.

Checkpoint contents

Task contract, policy version, current state, completed effects, pending effects, artifacts, evidence references, budgets, and safe resume instruction.

Exercise

Design a resumable three-step research workflow. Simulate interruption after step two and show how the checkpoint prevents repeating an external action.