DL-093
The Server’s durable session-transcript store is TWO-TIER: a Postgres hot-tail (agent_session_transcript_entries) holding [latest checkpoint..now] = the resume set, per-frame durable at the CommitConversationFrame seam and pruned at flush; superseded entries flush to an S3-compatible object-store cold archive (verbatim JSONL segments, PUT-before-prune, indexed by an agent_session_archive_segments manifest) at compaction (primary), a high size-cap safety valve, and session-end. Resume reads PG-only (S3 fallback only when the safety valve fired); the archive feeds the post-MVP opt-in analytics layer. Agent+Runner hold zero storage detail; the object-store client/credential is Server-internal (endpoint-agnostic: Garage/R2/MinIO). Realigns with DL-019
Status: Active (Matt, 2026-07-31)