spec: add eagle3-v3 support for gpt-oss model (#25794)

conversion/llama.py

@@ -69,9 +69,14 @@ class LlamaModel(TextModel):
                 target_config = {**target_config, **target_config["text_config"]}
             self.target_vocab_size = target_config["vocab_size"]
 
-            # target_layers: derived from target model layer count (low/mid/high)
+            # target_layers: use the eagle3 config's explicit aux hidden-state layer ids
+            # if present, else derive from the target layer count.
             target_num_layers = target_config["num_hidden_layers"]
-            target_layers = [2, target_num_layers // 2, target_num_layers - 3]
+            aux_layer_ids = eagle3_raw_config.get("eagle_aux_hidden_state_layer_ids")
+            if aux_layer_ids:
+                target_layers = aux_layer_ids
+            else:
+                target_layers = [2, target_num_layers // 2, target_num_layers - 3]
             logger.info(f"EAGLE-3: target_layers = {target_layers} (target model has {target_num_layers} layers)")
             self.gguf_writer.add_target_layers(target_layers)
 
@@ -90,6 +95,12 @@ class LlamaModel(TextModel):
             logger.info(f"EAGLE-3: norm_before_residual = {norm_before_residual}")
             self.gguf_writer.add_norm_before_residual(norm_before_residual)
 
+            # norm_before_fc: RMSNorm applied to the fused target features before the
+            # fc projection (e.g. nvidia/gpt-oss-120b-Eagle3-v3)
+            norm_before_fc = eagle3_raw_config.get("norm_before_fc", False)
+            logger.info(f"EAGLE-3: norm_before_fc = {norm_before_fc}")
+            self.gguf_writer.add_norm_before_fc(norm_before_fc)
+
     def set_vocab(self):
         # eagle3: use tokenizer from target model if provided
         original_dir_model = None
@@ -222,6 +233,9 @@ class LlamaModel(TextModel):
             if name == "fc.weight":
                 yield (name, data_torch)
                 return
+            if name == "input_norm.weight":
+                yield (self.format_tensor_name(gguf.MODEL_TENSOR.ENC_OUTPUT_NORM), data_torch)
+                return
             if name == "d2t":
                 # store for manual int64 handling in prepare_tensors (avoid F32 conversion)
                 if not hasattr(self, '_eagle3_int_tensors'):