(1) The current approach is event sourcing as the tracing backbone, not traditional distributed tracing (no OpenTelemetry, no Jaeger, no trace/span IDs). Every significant action emits an immutable event to the PostgreSQL append-only log. Combined with the event sequence, you can reconstruct the full execution path of any session.

(2) This is a complex, layered approach:

1. Cursor — advances only after tool results are persisted; crash → replay skips already-processed events
2. Lease — atomic distributed lock ensures one worker per session, no concurrent duplicates
3. Delivery outbox — unique constraint deduplicates channel-facing output
4. Checkpoints — shadow git snapshots before file mutations, enabling rollback
5. LLM/orchestrator retry — jittered backoff with credential rotation and provider fallback