DEC — Metrics are stored in a single flat (run_id, metric_name, value) table…
Metrics are stored in a single flat (run_id, metric_name, value) table with dot-separated keys for nested metrics, so new metrics need no schema change and runs can be pivoted/compared directly.
Source: PUMA project documentation · Traceability: corpus unit
PUMA-011· Confidence: repo-backed