{
 "schema_version": "0.2",
 "name": "[[18,4,3]]",
 "code_type": "CSS",
 "n": 18,
 "k": 4,
 "checks": {
  "X": [
   [
    0,
    6,
    8,
    13,
    14
   ],
   [
    0,
    3,
    4,
    6,
    9
   ],
   [
    10,
    12,
    13,
    16
   ],
   [
    0,
    2,
    13,
    15,
    17
   ],
   [
    1,
    2,
    11,
    16
   ],
   [
    3,
    4,
    7,
    11,
    14
   ],
   [
    0,
    4,
    5,
    10,
    15
   ]
  ],
  "Z": [
   [
    6,
    9,
    12,
    13,
    17
   ],
   [
    5,
    7,
    10,
    11,
    16
   ],
   [
    2,
    4,
    9,
    11,
    15
   ],
   [
    4,
    5,
    6,
    7,
    8
   ],
   [
    0,
    3,
    7,
    10,
    13
   ],
   [
    1,
    8,
    13,
    16,
    17
   ],
   [
    0,
    7,
    9,
    14,
    15
   ]
  ]
 },
 "distance": {
  "d": 3,
  "X": {
   "value": 3,
   "confidence": "upper_bound",
   "witness": [
    0,
    3,
    14
   ]
  },
  "Z": {
   "value": 3,
   "confidence": "upper_bound",
   "witness": [
    6,
    8,
    9
   ]
  }
 },
 "provenance": {
  "authors": [
   "@vprusso"
  ],
  "construction": "SAT-solver code discovery (arXiv:2608.23460 Sec. VI adapted to CSS): CNF over X/Z row-incidence variables, even-overlap commutation clauses for HX HZ^T = 0, per-error detection clauses for every Pauli of weight <= 2, and a Sinz sequential-counter bound of 5 on each row weight; solved with Minisat22 at n=18 with 7 rows per side",
  "origin": "submission",
  "date": "2026-08-26",
  "model": "Claude Fable 5"
 },
 "family": "other",
 "circuit": {
  "d_circ": {
   "X": {
    "value": 3,
    "confidence": "upper_bound",
    "witness": [
     2,
     7,
     13
    ]
   },
   "Z": {
    "value": 3,
    "confidence": "upper_bound",
    "witness": [
     195,
     196,
     274
    ]
   }
  },
  "rounds": 3,
  "stim_version": "1.16.0",
  "notes": "Generic sequential two-block extraction: one ancilla per check, X checks then Z checks each round with joint reset/measure layers; CX layers are a proper edge coloring of each Tanner graph (5 X + 5 Z CX layers per round, schedule seed 0; hook-aware orders: every CNOT order suffix needs >= d-1 further data errors to complete a logical, layered by min-conflicts search). Screened by RIS on ker(H_dem) and an observable-constrained seeded BP+OSD search; witnesses validated in GF(2).",
  "contributed_by": {
   "by": [
    "@vprusso"
   ],
   "date": "2026-09-16",
   "method": "generic CSS memory schedule: one ancilla per check, CX layers from a bipartite edge coloring, CNOT orders filtered by a hook-error criterion; screened by RIS on ker(H_dem) and an observable-constrained seeded BP+OSD search"
  },
  "ler": {
   "X": {
    "p": 0.001,
    "shots": 10000,
    "failures": 154,
    "seed": 7,
    "decoder": "bposd-cs-10",
    "ler_per_round": 0.005186956,
    "ci95": [
     0.004427739,
     0.006075606
    ]
   },
   "Z": {
    "p": 0.001,
    "shots": 10000,
    "failures": 123,
    "seed": 7,
    "decoder": "bposd-cs-10",
    "ler_per_round": 0.004134087,
    "ci95": [
     0.003463703,
     0.004933608
    ]
   }
  }
 },
 "locality": {
  "coordinates": [
   [
    1,
    3
   ],
   [
    2,
    5
   ],
   [
    2,
    4
   ],
   [
    1,
    0
   ],
   [
    2,
    0
   ],
   [
    0,
    0
   ],
   [
    1,
    2
   ],
   [
    2,
    1
   ],
   [
    0,
    2
   ],
   [
    2,
    3
   ],
   [
    1,
    1
   ],
   [
    2,
    2
   ],
   [
    1,
    5
   ],
   [
    1,
    4
   ],
   [
    0,
    1
   ],
   [
    0,
    3
   ],
   [
    0,
    4
   ],
   [
    0,
    5
   ]
  ],
  "layers": 1,
  "contributed_by": {
   "by": [
    "@mathysrennela"
   ],
   "date": "2026-09-19",
   "method": "simulated annealing over integer grid sites (research/local2d/fold_layout.py)"
  }
 }
}