diff --git a/join-use-case/model-optimization.mdx b/join-use-case/model-optimization.mdx
index 56ecde7..974528d 100644
--- a/join-use-case/model-optimization.mdx
+++ b/join-use-case/model-optimization.mdx
@@ -19,6 +19,29 @@ model/
     - model_weights.pkl
 ```
 
+## Models build locally (no external hubs)
+
+Your model file must build its architecture from local code. tracebloc does not
+fetch models, weights, tokenizers, or configs from an external hub (such as
+HuggingFace) while training — a training pod has no such egress. In practice your
+model file must **not**:
+
+- call `*.from_pretrained("<hub-id>")` for a model, tokenizer, or config, or
+- declare a `model_id`, `tokenizer_id`, or `hf_token` variable.
+
+To start from a pretrained model, download its weights once, build the same
+architecture in your model file, and upload the weights alongside it (see
+[Use pre-trained weights](#use-pre-trained-weights)). For text and other NLP
+tasks, also ship a `tokenizer.json` — pass it with
+`user.upload_model(..., tokenizer="tokenizer.json")` or place it next to your
+model file.
+
+<Note>
+The uploaded weights file is loaded into the architecture your model file builds,
+matching parameter names and shapes exactly. Build the same architecture you
+produced the weights from, or the load will fail.
+</Note>
+
 ## Model Code Formats
 
 Model code can be:
@@ -67,8 +90,10 @@ Each format must contain these variables on the main file:
 
 Some additional variables are required for specific categories
 * **num_feature_points** : number of keypoints or feature points for which this model file is created. This variable is used only for keypoint_detection and generic_classification category.
-* **model_id** : model id using which this model file is created. This variable is used only for text_classification category.
-* **hf_token** : hf token using which this model file is created. This variable is used only for text_classification category.
+
+<Note>
+`model_id`, `tokenizer_id`, and `hf_token` are no longer supported — hub-referenced models are not accepted. See [Models build locally (no external hubs)](#models-build-locally-no-external-hubs).
+</Note>
 
 <Warning>
 * The framework variable is compulsory and should always be placed at the top of your code just after the imports, before any other variable.