diff --git a/api/app/controllers/prompt_optimizer_controller.py b/api/app/controllers/prompt_optimizer_controller.py
index 2cda65ac..d647f0c0 100644
--- a/api/app/controllers/prompt_optimizer_controller.py
+++ b/api/app/controllers/prompt_optimizer_controller.py
@@ -163,7 +163,7 @@ def set_system_prompt(
 
     model_config = PromptOptimizerService(db).create_update_model_config(
         current_user.tenant_id,
-        data.id, data.model_id,
+        data.id,
         data.system_prompt
     )
     return success(data=model_config.id)
diff --git a/api/app/models/prompt_optimizer_model.py b/api/app/models/prompt_optimizer_model.py
index 9bb78acf..5191fc2e 100644
--- a/api/app/models/prompt_optimizer_model.py
+++ b/api/app/models/prompt_optimizer_model.py
@@ -86,12 +86,10 @@ class PromptOptimizerSession(Base):
 
     Columns:
         id (UUID):
-            Primary key. Internal unique identifier for the session record.
+            Public-facing session identifier used to group conversation history.
         tenant_id (UUID):
             Foreign key referencing `tenants.id`.
             Identifies the tenant under which the session is created.
-        session_id (UUID):
-            Public-facing session identifier used to group conversation history.
         user_id (UUID):
             Foreign key referencing `users.id`.
             Identifies the user who initiated the session.
@@ -105,10 +103,9 @@ class PromptOptimizerSession(Base):
     """
     __tablename__ = "prompt_opt_session_list"
 
-    id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4, index=True)
+    id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4, index=True, comment="Session ID")
     tenant_id = Column(UUID(as_uuid=True), ForeignKey("tenants.id"), nullable=False, comment="Tenant ID")
     # app_id = Column(UUID(as_uuid=True), ForeignKey("apps.id"), nullable=False, comment="Application ID")
-    session_id = Column(UUID(as_uuid=True), nullable=False, comment="Session ID")
     user_id = Column(UUID(as_uuid=True), ForeignKey("users.id"), nullable=False, comment="User ID")
 
     created_at = Column(DateTime, default=datetime.datetime.now, comment="Creation Time", index=True)
diff --git a/api/app/repositories/prompt_optimizer_repository.py b/api/app/repositories/prompt_optimizer_repository.py
index a159981d..ecb2af98 100644
--- a/api/app/repositories/prompt_optimizer_repository.py
+++ b/api/app/repositories/prompt_optimizer_repository.py
@@ -141,7 +141,6 @@ class PromptOptimizerSessionRepository:
             session = PromptOptimizerSession(
                 tenant_id=tenant_id,
                 user_id=user_id,
-                session_id=uuid.uuid4(),
             )
             self.db.add(session)
             self.db.commit()
@@ -172,8 +171,17 @@ class PromptOptimizerSessionRepository:
                         f"user_id={user_id}, session_id={session_id}")
 
         try:
+            # First get the internal session ID from the session list table
+            session = self.db.query(PromptOptimizerSession).filter(
+                PromptOptimizerSession.id == session_id,
+                PromptOptimizerSession.user_id == user_id
+            ).first()
+            
+            if not session:
+                return []
+            
             history = self.db.query(PromptOptimizerSessionHistory).filter(
-                PromptOptimizerSessionHistory.session_id == session_id,
+                PromptOptimizerSessionHistory.session_id == session.id,
                 PromptOptimizerSessionHistory.user_id == user_id
             ).order_by(PromptOptimizerSessionHistory.created_at.asc()).all()
             return history
@@ -195,9 +203,20 @@ class PromptOptimizerSessionRepository:
         This method is a placeholder for future implementation.
         """
         try:
+            # Get the session to ensure it exists and belongs to the user
+            session = self.db.query(PromptOptimizerSession).filter(
+                PromptOptimizerSession.id == session_id,
+                PromptOptimizerSession.user_id == user_id,
+                PromptOptimizerSession.tenant_id == tenant_id
+            ).first()
+            
+            if not session:
+                db_logger.error(f"Session {session_id} not found for user {user_id}")
+                raise ValueError(f"Session {session_id} not found for user {user_id}")
+            
             message = PromptOptimizerSessionHistory(
                 tenant_id=tenant_id,
-                session_id=session_id,
+                session_id=session.id,
                 user_id=user_id,
                 role=role.value,
                 content=content,
diff --git a/api/app/services/prompt_optimizer_service.py b/api/app/services/prompt_optimizer_service.py
index 9a70c24f..0cdaabf5 100644
--- a/api/app/services/prompt_optimizer_service.py
+++ b/api/app/services/prompt_optimizer_service.py
@@ -73,7 +73,6 @@ class PromptOptimizerService:
             self,
             tenant_id: uuid.UUID,
             config_id: uuid.UUID,
-            model_id: uuid.UUID,
             system_prompt: str,
     ) -> PromptOptimizerModelConfig:
         """
@@ -86,7 +85,6 @@ class PromptOptimizerService:
         Args:
             tenant_id (uuid.UUID): The unique identifier of the tenant.
             config_id (uuid.UUID): The unique identifier of the configuration to create or update.
-            model_id (uuid.UUID): The unique identifier of the model associated with this configuration.
             system_prompt (str): The system prompt content used for prompt optimization.
 
         Returns: