diff --git a/services/ml_training_service/proto/ml_training.proto b/services/ml_training_service/proto/ml_training.proto
index 83e136318..8da27f879 100644
--- a/services/ml_training_service/proto/ml_training.proto
+++ b/services/ml_training_service/proto/ml_training.proto
@@ -67,6 +67,12 @@ service MLTrainingService {
 
 // --- Core Request/Response Messages ---
 
+// Training mode selection
+enum TrainingMode {
+  TRAINING_MODE_FULL = 0;        // Full training from scratch (default, backward-compatible)
+  TRAINING_MODE_FINE_TUNE = 1;   // Fine-tune from existing checkpoint
+}
+
 // Request to start a new model training job
 message StartTrainingRequest {
   string model_type = 1;                // Model type ("TLOB", "MAMBA_2", "DQN", "PPO", "LIQUID", "TFT")
@@ -75,6 +81,9 @@ message StartTrainingRequest {
   bool use_gpu = 4;                     // Whether to use GPU acceleration
   string description = 5;               // Optional job description
   map<string, string> tags = 6;         // Optional categorization tags
+  TrainingMode mode = 7;               // FULL (default) or FINE_TUNE
+  string resume_checkpoint_path = 8;   // Path to checkpoint for fine-tune
+  uint32 max_epochs = 9;              // Override epoch count (0 = use default)
 }
 
 message StartTrainingResponse {