{
  "seed": 20260831,
  "briefs": 210,
  "marginals": {
    "industry": {
      "values": 10,
      "briefs_per_value": 21
    },
    "tone": {
      "values": 6,
      "briefs_per_value": 35
    },
    "medium": {
      "values": 6,
      "briefs_per_value": 35
    },
    "script": {
      "values": 5,
      "briefs_per_value": 42
    },
    "specificity": {
      "values": 3,
      "briefs_per_value": 70
    }
  },
  "pairwise": {
    "cells_possible": 347,
    "cells_occupied": 347,
    "cell_count_min": 2,
    "cell_count_max": 14,
    "note": "Occupancy is not balance. Every pair of tag values appears, but counts range from 2 to 14."
  },
  "three_way": {
    "dimensions": [
      "tone",
      "script",
      "specificity"
    ],
    "cells_possible": 90,
    "cells_occupied": 89,
    "note": "One cell of ninety is empty, so higher-order confounding is reduced rather than eliminated."
  },
  "regeneration": "src/build_brief_grid.py assigns exact marginals, then hill-climbs pair occupancy. Seed above reproduces the grid."
}