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      "validation_selected_arm": "exact-grpo",
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      "limitations": [
        "MovieLens history and rating utility replace private query/click/order sessions.",
        "Small random-initialized Transformer replaces GPT-2 Small; no pretrained language claim.",
        "Public genre/title attributes replace private multimodal semantic features.",
        "This is a bounded mechanism diagnostic, not stable improvement or production A/B reproduction.",
        "SID collisions retain stable item-ID ties; no extra collision resolution learned."
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  "evaluation_protocol": {
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    "seeds": [
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    "formal_comparison": false,
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    "claim_policy": "bounded public-data mechanism diagnostic; no stable/production gain"
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  "provenance": {
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    "artifact_path": "docs/reproductions/2610.16979-wegr/metrics/public-a100-seeds42-44.json",
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    "Small random-initialized Transformer replaces GPT-2 Small; no pretrained language claim.",
    "Public genre/title attributes replace private multimodal semantic features.",
    "This is a bounded mechanism diagnostic, not stable improvement or production A/B reproduction.",
    "SID collisions retain stable item-ID ties; no extra collision resolution learned."
  ]
}