{
  "experiment": "A5 decoder-aware gate gap diagnosis",
  "protocol": "protocol4_limit10",
  "inputs": {
    "a3_sparse_preflight": "vggt_spatial_adapter/support_guidance_a3_sparse_preflight/analysis.json",
    "a4_selected_alpha_decode": "vggt_spatial_adapter/support_guidance_a4_selected_alpha_decode/analysis.json",
    "single_case_sparse_trajectory": "vggt_spatial_adapter/baseline_preserving_v2/step25_sparse_trajectory.json"
  },
  "trajectory_evidence": {
    "case_id": "gso_000_input4",
    "initial_noise_exact_equal": true,
    "first_latent_divergent_step": 1,
    "first_occupancy_divergent_step": 6,
    "final_sparse_jaccard": 0.0,
    "final_uniform_count": 26,
    "final_adapter_count": 24,
    "effective_condition_delta_rms": 0.00015158970199991018
  },
  "aggregate": {
    "case_count": 10,
    "sparse_gate_passed_count": 10,
    "decode_ok_count": 9,
    "decode_failed_count": 1,
    "sparse_pass_decode_failed_count": 1,
    "exact_sparse_match_but_decode_failed_count": 1,
    "exact_sparse_match_but_decode_failed_cases": [
      "gso_000_input4"
    ],
    "decode_empty_tensor_error_count": 1,
    "chamfer_improved_count": 3,
    "chamfer_worse_count": 4,
    "chamfer_unchanged_count": 2,
    "mean_chamfer_delta_decode_ok": 0.001011124289581008,
    "mean_fscore_5pct_delta_decode_ok": 0.00262576755412772,
    "raw_watertight_rate_decode_ok": 0.0,
    "uniform_token_median": 1361.0,
    "min_uniform_token_count": 26,
    "failure_class_counts": {
      "sparse_pass_decode_empty": 1,
      "decode_ok_topology_open": 5,
      "decode_ok_geometry_worse_topology_open": 4
    }
  },
  "rows": [
    {
      "case_id": "gso_000_input4",
      "selected_alpha": 0.125,
      "uniform_token_count": 26,
      "selected_token_count": 26,
      "selected_token_ratio": 1.0,
      "selected_sparse_jaccard": 1.0,
      "selected_centroid_distance": 0.0,
      "selected_sparse_exact_equal": true,
      "sparse_gate_passed": true,
      "low_token_case": true,
      "selected_generation_status": "failed",
      "selected_eval_status": "missing_prediction",
      "selected_error": "RuntimeError: max(): Expected reduction dim to be specified for input.numel() == 0. Specify the reduction dim with the 'dim' argument.",
      "decode_empty_tensor_error": true,
      "selected_delta_chamfer_mean": null,
      "selected_delta_fscore_5pct": null,
      "selected_watertight": null,
      "selected_boundary_edges": null,
      "selected_nonmanifold_edges": null,
      "failure_class": "sparse_pass_decode_empty",
      "failure_reason": "sparse support gate passed, but full decode failed before mesh extraction"
    },
    {
      "case_id": "gso_001_input4",
      "selected_alpha": 1.0,
      "uniform_token_count": 842,
      "selected_token_count": 836,
      "selected_token_ratio": 0.9928741092636579,
      "selected_sparse_jaccard": 0.9928741092636579,
      "selected_centroid_distance": 0.03290579716986058,
      "selected_sparse_exact_equal": false,
      "sparse_gate_passed": true,
      "low_token_case": true,
      "selected_generation_status": "ok",
      "selected_eval_status": "ok",
      "selected_error": null,
      "decode_empty_tensor_error": false,
      "selected_delta_chamfer_mean": -0.0021055093913970313,
      "selected_delta_fscore_5pct": 0.008067967797955156,
      "selected_watertight": 0.0,
      "selected_boundary_edges": 1133,
      "selected_nonmanifold_edges": 2364,
      "failure_class": "decode_ok_topology_open",
      "failure_reason": "full decode produced a mesh, but raw topology stayed open"
    },
    {
      "case_id": "gso_002_input4",
      "selected_alpha": 1.0,
      "uniform_token_count": 3082,
      "selected_token_count": 3314,
      "selected_token_ratio": 1.0752757949383518,
      "selected_sparse_jaccard": 0.8337155963302753,
      "selected_centroid_distance": 1.7103037208502745,
      "selected_sparse_exact_equal": false,
      "sparse_gate_passed": true,
      "low_token_case": false,
      "selected_generation_status": "ok",
      "selected_eval_status": "ok",
      "selected_error": null,
      "decode_empty_tensor_error": false,
      "selected_delta_chamfer_mean": -0.0001380902420319366,
      "selected_delta_fscore_5pct": 0.006357535229210676,
      "selected_watertight": 0.0,
      "selected_boundary_edges": 10155,
      "selected_nonmanifold_edges": 9221,
      "failure_class": "decode_ok_topology_open",
      "failure_reason": "full decode produced a mesh, but raw topology stayed open"
    },
    {
      "case_id": "gso_003_input4",
      "selected_alpha": 1.0,
      "uniform_token_count": 5097,
      "selected_token_count": 5083,
      "selected_token_ratio": 0.9972532862468119,
      "selected_sparse_jaccard": 0.9524357499041043,
      "selected_centroid_distance": 0.06882564784752744,
      "selected_sparse_exact_equal": false,
      "sparse_gate_passed": true,
      "low_token_case": false,
      "selected_generation_status": "ok",
      "selected_eval_status": "ok",
      "selected_error": null,
      "decode_empty_tensor_error": false,
      "selected_delta_chamfer_mean": -1.1446424334815575e-05,
      "selected_delta_fscore_5pct": -0.00027421872447597195,
      "selected_watertight": 0.0,
      "selected_boundary_edges": 1733,
      "selected_nonmanifold_edges": 11400,
      "failure_class": "decode_ok_topology_open",
      "failure_reason": "full decode produced a mesh, but raw topology stayed open"
    },
    {
      "case_id": "gso_004_input4",
      "selected_alpha": 1.0,
      "uniform_token_count": 2452,
      "selected_token_count": 2452,
      "selected_token_ratio": 1.0,
      "selected_sparse_jaccard": 1.0,
      "selected_centroid_distance": 0.0,
      "selected_sparse_exact_equal": true,
      "sparse_gate_passed": true,
      "low_token_case": false,
      "selected_generation_status": "ok",
      "selected_eval_status": "ok",
      "selected_error": null,
      "decode_empty_tensor_error": false,
      "selected_delta_chamfer_mean": 0.0,
      "selected_delta_fscore_5pct": 0.0,
      "selected_watertight": 0.0,
      "selected_boundary_edges": 2843,
      "selected_nonmanifold_edges": 4830,
      "failure_class": "decode_ok_topology_open",
      "failure_reason": "full decode produced a mesh, but raw topology stayed open"
    },
    {
      "case_id": "gso_005_input4",
      "selected_alpha": 1.0,
      "uniform_token_count": 392,
      "selected_token_count": 392,
      "selected_token_ratio": 1.0,
      "selected_sparse_jaccard": 1.0,
      "selected_centroid_distance": 0.0,
      "selected_sparse_exact_equal": true,
      "sparse_gate_passed": true,
      "low_token_case": true,
      "selected_generation_status": "ok",
      "selected_eval_status": "ok",
      "selected_error": null,
      "decode_empty_tensor_error": false,
      "selected_delta_chamfer_mean": 0.0,
      "selected_delta_fscore_5pct": 0.0,
      "selected_watertight": 0.0,
      "selected_boundary_edges": 3127,
      "selected_nonmanifold_edges": 4862,
      "failure_class": "decode_ok_topology_open",
      "failure_reason": "full decode produced a mesh, but raw topology stayed open"
    },
    {
      "case_id": "gso_006_input4",
      "selected_alpha": 1.0,
      "uniform_token_count": 1393,
      "selected_token_count": 1414,
      "selected_token_ratio": 1.015075376884422,
      "selected_sparse_jaccard": 0.9712078651685393,
      "selected_centroid_distance": 0.151179193171909,
      "selected_sparse_exact_equal": false,
      "sparse_gate_passed": true,
      "low_token_case": false,
      "selected_generation_status": "ok",
      "selected_eval_status": "ok",
      "selected_error": null,
      "decode_empty_tensor_error": false,
      "selected_delta_chamfer_mean": 0.0006965113438393983,
      "selected_delta_fscore_5pct": -0.0022388525123019365,
      "selected_watertight": 0.0,
      "selected_boundary_edges": 32915,
      "selected_nonmanifold_edges": 46856,
      "failure_class": "decode_ok_geometry_worse_topology_open",
      "failure_reason": "full decode produced a mesh, but geometry worsened and raw topology stayed open"
    },
    {
      "case_id": "gso_007_input4",
      "selected_alpha": 1.0,
      "uniform_token_count": 995,
      "selected_token_count": 991,
      "selected_token_ratio": 0.9959798994974874,
      "selected_sparse_jaccard": 0.986,
      "selected_centroid_distance": 0.004664139821296307,
      "selected_sparse_exact_equal": false,
      "sparse_gate_passed": true,
      "low_token_case": true,
      "selected_generation_status": "ok",
      "selected_eval_status": "ok",
      "selected_error": null,
      "decode_empty_tensor_error": false,
      "selected_delta_chamfer_mean": 0.0017336753849026276,
      "selected_delta_fscore_5pct": 0.003577660256786741,
      "selected_watertight": 0.0,
      "selected_boundary_edges": 4303,
      "selected_nonmanifold_edges": 7187,
      "failure_class": "decode_ok_geometry_worse_topology_open",
      "failure_reason": "full decode produced a mesh, but geometry worsened and raw topology stayed open"
    },
    {
      "case_id": "gso_008_input4",
      "selected_alpha": 1.0,
      "uniform_token_count": 1423,
      "selected_token_count": 1446,
      "selected_token_ratio": 1.016163035839775,
      "selected_sparse_jaccard": 0.967764060356653,
      "selected_centroid_distance": 0.034458275927452264,
      "selected_sparse_exact_equal": false,
      "sparse_gate_passed": true,
      "low_token_case": false,
      "selected_generation_status": "ok",
      "selected_eval_status": "ok",
      "selected_error": null,
      "decode_empty_tensor_error": false,
      "selected_delta_chamfer_mean": 0.005774633795956469,
      "selected_delta_fscore_5pct": -0.01390692598131299,
      "selected_watertight": 0.0,
      "selected_boundary_edges": 43223,
      "selected_nonmanifold_edges": 1034,
      "failure_class": "decode_ok_geometry_worse_topology_open",
      "failure_reason": "full decode produced a mesh, but geometry worsened and raw topology stayed open"
    },
    {
      "case_id": "gso_009_input4",
      "selected_alpha": 1.0,
      "uniform_token_count": 1329,
      "selected_token_count": 1258,
      "selected_token_ratio": 0.9465763732129421,
      "selected_sparse_jaccard": 0.8386638237384506,
      "selected_centroid_distance": 0.8296855921152545,
      "selected_sparse_exact_equal": false,
      "sparse_gate_passed": true,
      "low_token_case": true,
      "selected_generation_status": "ok",
      "selected_eval_status": "ok",
      "selected_error": null,
      "decode_empty_tensor_error": false,
      "selected_delta_chamfer_mean": 0.00315034413929436,
      "selected_delta_fscore_5pct": 0.022048741921287807,
      "selected_watertight": 0.0,
      "selected_boundary_edges": 3837,
      "selected_nonmanifold_edges": 7520,
      "failure_class": "decode_ok_geometry_worse_topology_open",
      "failure_reason": "full decode produced a mesh, but geometry worsened and raw topology stayed open"
    }
  ],
  "conclusion": [
    "A5 confirms a concrete sparse-to-decoder gap: gso_000_input4 has an exact selected sparse support match, yet full decode fails with an empty-tensor error.",
    "Sparse token ratio, Jaccard, centroid drift, and exact support equality are necessary safety checks, but they are not sufficient after the shape/decoder stage begins.",
    "The next paper-worthy direction is a decoder-aware occupancy or SLat viability gate that rejects a VGGT residual before full mesh extraction if the decoded band collapses, explodes, or drifts from the baseline."
  ],
  "limitations": [
    "A5 is a diagnostic aggregation over existing A3/A4 outputs, not a newly trained model.",
    "Full shape-SLat occupancy was not captured for all 10 cases, so the empty decode root cause is inferred from sparse equality plus TRELLIS.2 runtime error.",
    "The experiment uses protocol4_limit10; the gate still needs validation on the 100-case 2/4/6/8 matrix."
  ],
  "next_steps": [
    "Instrument TRELLIS.2 shape-SLat sampling to capture active token count, decoded occupancy fraction, centroid, and extent before mesh extraction.",
    "Define a two-stage gate: sparse support gate first, then decoder occupancy viability gate.",
    "Route baseline, selected-alpha, and repair candidates through a no-extra-failure selector before larger-scale evaluation."
  ]
}