{
 "schema_version": "1.7.0",
 "id": "x_NXMC-2022-0010",
 "modified": "2026-10-19T02:33:38.839Z",
 "published": "2026-10-18T09:00:52.565Z",
 "summary": "opt-125m: tokenizer change at da93426 (2022-05-26)",
 "details": "opt-125m: BOS changed from 0 to 2; prompts built by the old tokenizer start with a different token (2022-05-26).\n\nRepository: https://huggingface.co/facebook/opt-125m. Revisions from da9342600c033a6a5fbf1f3e9a75839107ecd887 onward carry this change; a pin at 1c370c849af40849404742f4d5ce1c2a0f82add2 or earlier does not.\n\nChanged keys:\n- bos_token_id: 0 -> 2 (tokenizer)\n\nThis record says what the change does mechanically. It is not a report that anything broke for anyone.",
 "affected": [
  {
   "ranges": [
    {
     "type": "GIT",
     "repo": "https://huggingface.co/facebook/opt-125m",
     "events": [
      {
       "introduced": "da9342600c033a6a5fbf1f3e9a75839107ecd887"
      }
     ]
    }
   ],
   "database_specific": {
    "model": "facebook/opt-125m",
    "previous_revision": "1c370c849af40849404742f4d5ce1c2a0f82add2"
   }
  }
 ],
 "references": [
  {
   "type": "INTRODUCED",
   "url": "https://huggingface.co/facebook/opt-125m/commit/da9342600c033a6a5fbf1f3e9a75839107ecd887"
  },
  {
   "type": "PACKAGE",
   "url": "https://huggingface.co/facebook/opt-125m"
  },
  {
   "type": "WEB",
   "url": "https://www.neurarch.com/changes-feeds/models/facebook/opt-125m.html"
  }
 ],
 "database_specific": {
  "source": "neurarch model change tracker",
  "model": "facebook/opt-125m",
  "kind": "tokenizer",
  "classes": [
   "tokenizer"
  ],
  "changed_keys": [
   {
    "file": "config",
    "key": "bos_token_id",
    "before": 0,
    "after": 2,
    "class": "tokenizer"
   }
  ],
  "impact": {
   "memory": false,
   "serving": true,
   "tokenizer": true,
   "licence": null
  },
  "breaking": true,
  "breaking_rule": "https://www.neurarch.com/changes-feeds/advisories/index.json#breaking_rule",
  "consequence": {
   "params": null,
   "weightsGbBf16": null,
   "trainPeakGb": null,
   "fingerprint": null,
   "context": null,
   "eos": null,
   "bos": {
    "before": 0,
    "after": 2
   }
  },
  "commit_date": "2022-05-26T15:44:08.000Z",
  "detected_at": "2026-10-18T09:00:52.565Z",
  "detected_by": "backfill",
  "days_since_first_commit": 14,
  "license": "CC-BY-4.0"
 }
}