{
 "schema_version": "1.7.0",
 "id": "x_NXMC-2026-0002",
 "modified": "2026-10-19T02:33:38.839Z",
 "published": "2026-10-18T09:00:52.565Z",
 "summary": "ESMC-6B: structural change at 7fe0068 (2026-09-14)",
 "details": "ESMC-6B: EOS declared as 2 (was unset); generation that relied on the library default now stops on this token; BOS declared as 0 (was unset); head dim unset to 64, MLP width unset to 6912, attention heads unset to 40, layer count unset to 80, KV heads unset to 40 (2026-09-14).\n\nRepository: https://huggingface.co/biohub/ESMC-6B. Revisions from 7fe00682557aa7688b19a4dbcb21b267da99b7e6 onward carry this change; a pin at 2f13fa295be39898399cf7f6b0a97c26a13d5b3c or earlier does not.\n\nChanged keys:\n- architectures: [\"ESMCForMaskedLM\"] -> [\"EsmcForMaskedLM\"] (structural)\n- bos_token_id: unset -> 0 (tokenizer)\n- eos_token_id: unset -> 2 (tokenizer)\n- head_dim: unset -> 64 (structural)\n- intermediate_size: unset -> 6912 (structural)\n- max_position_embeddings: unset -> 2048 (structural)\n- num_attention_heads: unset -> 40 (structural)\n- num_hidden_layers: unset -> 80 (structural)\n- num_key_value_heads: unset -> 40 (structural)\n- rope_theta: unset -> 10000 (structural)\n- tokenizer tokenizer_class: ESMCTokenizer -> EsmcTokenizer (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/biohub/ESMC-6B",
     "events": [
      {
       "introduced": "7fe00682557aa7688b19a4dbcb21b267da99b7e6"
      }
     ]
    }
   ],
   "database_specific": {
    "model": "biohub/ESMC-6B",
    "previous_revision": "2f13fa295be39898399cf7f6b0a97c26a13d5b3c"
   }
  }
 ],
 "references": [
  {
   "type": "INTRODUCED",
   "url": "https://huggingface.co/biohub/ESMC-6B/commit/7fe00682557aa7688b19a4dbcb21b267da99b7e6"
  },
  {
   "type": "PACKAGE",
   "url": "https://huggingface.co/biohub/ESMC-6B"
  },
  {
   "type": "WEB",
   "url": "https://www.neurarch.com/changes-feeds/models/biohub/ESMC-6B.html"
  }
 ],
 "database_specific": {
  "source": "neurarch model change tracker",
  "model": "biohub/ESMC-6B",
  "kind": "structural",
  "classes": [
   "structural",
   "tokenizer"
  ],
  "changed_keys": [
   {
    "file": "config",
    "key": "architectures",
    "before": [
     "ESMCForMaskedLM"
    ],
    "after": [
     "EsmcForMaskedLM"
    ],
    "class": "structural"
   },
   {
    "file": "config",
    "key": "bos_token_id",
    "before": null,
    "after": 0,
    "class": "tokenizer"
   },
   {
    "file": "config",
    "key": "eos_token_id",
    "before": null,
    "after": 2,
    "class": "tokenizer"
   },
   {
    "file": "config",
    "key": "head_dim",
    "before": null,
    "after": 64,
    "class": "structural"
   },
   {
    "file": "config",
    "key": "intermediate_size",
    "before": null,
    "after": 6912,
    "class": "structural"
   },
   {
    "file": "config",
    "key": "max_position_embeddings",
    "before": null,
    "after": 2048,
    "class": "structural"
   },
   {
    "file": "config",
    "key": "num_attention_heads",
    "before": null,
    "after": 40,
    "class": "structural"
   },
   {
    "file": "config",
    "key": "num_hidden_layers",
    "before": null,
    "after": 80,
    "class": "structural"
   },
   {
    "file": "config",
    "key": "num_key_value_heads",
    "before": null,
    "after": 40,
    "class": "structural"
   },
   {
    "file": "config",
    "key": "rope_theta",
    "before": null,
    "after": 10000,
    "class": "structural"
   },
   {
    "file": "tokenizer",
    "key": "tokenizer_class",
    "before": "ESMCTokenizer",
    "after": "EsmcTokenizer",
    "class": "tokenizer"
   }
  ],
  "impact": {
   "memory": true,
   "serving": true,
   "tokenizer": true,
   "licence": null
  },
  "breaking": true,
  "breaking_rule": "https://www.neurarch.com/changes-feeds/advisories/index.json#breaking_rule",
  "consequence": {
   "params": {
    "before": 3358597120,
    "after": 4935700480
   },
   "weightsGbBf16": {
    "before": 6.717,
    "after": 9.871
   },
   "trainPeakGb": {
    "before": 128.014,
    "after": 456.812
   },
   "fingerprint": null,
   "context": {
    "before": null,
    "after": 2048
   },
   "eos": {
    "before": null,
    "after": 2
   },
   "bos": {
    "before": null,
    "after": 0
   }
  },
  "commit_date": "2026-09-14T19:45:56.000Z",
  "detected_at": "2026-10-18T09:00:52.565Z",
  "detected_by": "backfill",
  "days_since_first_commit": 117,
  "license": "CC-BY-4.0"
 }
}