diff --git a/src/ea_chatbot/api/dependencies.py b/src/ea_chatbot/api/dependencies.py
index 84fdddd..fe0f533 100644
--- a/src/ea_chatbot/api/dependencies.py
+++ b/src/ea_chatbot/api/dependencies.py
@@ -35,11 +35,11 @@ async def get_current_user(token: str = Depends(oauth2_scheme)) -> User:
     if payload is None:
         raise credentials_exception
         
-    username: str | None = payload.get("sub")
-    if username is None:
+    user_id: str | None = payload.get("sub")
+    if user_id is None:
         raise credentials_exception
         
-    user = history_manager.get_user(username)
+    user = history_manager.get_user_by_id(user_id)
     if user is None:
         raise credentials_exception
         
diff --git a/src/ea_chatbot/api/routers/auth.py b/src/ea_chatbot/api/routers/auth.py
index 28d4953..96beb9c 100644
--- a/src/ea_chatbot/api/routers/auth.py
+++ b/src/ea_chatbot/api/routers/auth.py
@@ -39,7 +39,7 @@ async def login(form_data: OAuth2PasswordRequestForm = Depends()):
             headers={"WWW-Authenticate": "Bearer"},
         )
     
-    access_token = create_access_token(data={"sub": user.username, "user_id": str(user.id)})
+    access_token = create_access_token(data={"sub": str(user.id)})
     return {"access_token": access_token, "token_type": "bearer"}
 
 @router.get("/oidc/login")
@@ -71,7 +71,7 @@ async def oidc_callback(code: str):
             
         user = history_manager.sync_user_from_oidc(email=email, display_name=name)
         
-        access_token = create_access_token(data={"sub": user.username, "user_id": str(user.id)})
+        access_token = create_access_token(data={"sub": str(user.id)})
         return {"access_token": access_token, "token_type": "bearer"}
     except Exception as e:
         raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail=f"OIDC authentication failed: {str(e)}")
diff --git a/src/ea_chatbot/api/utils.py b/src/ea_chatbot/api/utils.py
index a775095..4019dcd 100644
--- a/src/ea_chatbot/api/utils.py
+++ b/src/ea_chatbot/api/utils.py
@@ -19,12 +19,18 @@ def create_access_token(data: dict, expires_delta: Optional[timedelta] = None) -
         str: The encoded JWT token.
     """
     to_encode = data.copy()
-    if expires_delta:
-        expire = datetime.now(timezone.utc) + expires_delta
-    else:
-        expire = datetime.now(timezone.utc) + timedelta(minutes=settings.access_token_expire_minutes)
+    now = datetime.now(timezone.utc)
     
-    to_encode.update({"exp": expire})
+    if expires_delta:
+        expire = now + expires_delta
+    else:
+        expire = now + timedelta(minutes=settings.access_token_expire_minutes)
+    
+    to_encode.update({
+        "exp": expire,
+        "iat": now,
+        "iss": "ea-chatbot-api"
+    })
     encoded_jwt = jwt.encode(to_encode, settings.secret_key, algorithm=settings.algorithm)
     return encoded_jwt
 
diff --git a/src/ea_chatbot/history/manager.py b/src/ea_chatbot/history/manager.py
index aa3c06e..6adc8a1 100644
--- a/src/ea_chatbot/history/manager.py
+++ b/src/ea_chatbot/history/manager.py
@@ -39,6 +39,11 @@ class HistoryManager:
             result = session.execute(select(User).where(User.username == email))
             return result.scalar_one_or_none()
 
+    def get_user_by_id(self, user_id: str) -> Optional[User]:
+        """Fetch a user by their ID."""
+        with self.get_session() as session:
+            return session.get(User, user_id)
+
     def create_user(self, email: str, password: Optional[str] = None, display_name: Optional[str] = None) -> User:
         """Create a new local user."""
         hashed_password = ph.hash(password) if password else None
diff --git a/tests/api/test_agent.py b/tests/api/test_agent.py
index ae4f21b..09fc007 100644
--- a/tests/api/test_agent.py
+++ b/tests/api/test_agent.py
@@ -15,7 +15,7 @@ def mock_user():
 @pytest.fixture
 def auth_header(mock_user):
     app.dependency_overrides[get_current_user] = lambda: mock_user
-    token = create_access_token(data={"sub": mock_user.username, "user_id": mock_user.id})
+    token = create_access_token(data={"sub": mock_user.id})
     yield {"Authorization": f"Bearer {token}"}
     app.dependency_overrides.clear()
 
diff --git a/tests/api/test_api_auth.py b/tests/api/test_api_auth.py
index a97dac7..9b8d94c 100644
--- a/tests/api/test_api_auth.py
+++ b/tests/api/test_api_auth.py
@@ -92,10 +92,10 @@ def test_oidc_callback_success():
 def test_get_me_success():
     """Test getting current user with a valid token."""
     from ea_chatbot.api.utils import create_access_token
-    token = create_access_token(data={"sub": "test@example.com", "user_id": "123"})
+    token = create_access_token(data={"sub": "123"})
     
     with patch("ea_chatbot.api.dependencies.history_manager") as mock_hm:
-        mock_hm.get_user.return_value = User(id="123", username="test@example.com", display_name="Test")
+        mock_hm.get_user_by_id.return_value = User(id="123", username="test@example.com", display_name="Test")
         
         response = client.get(
             "/auth/me",
diff --git a/tests/api/test_api_history.py b/tests/api/test_api_history.py
index 5e0a76b..d322e44 100644
--- a/tests/api/test_api_history.py
+++ b/tests/api/test_api_history.py
@@ -18,7 +18,7 @@ def mock_user():
 def auth_header(mock_user):
     # Override get_current_user to return our mock user
     app.dependency_overrides[get_current_user] = lambda: mock_user
-    token = create_access_token(data={"sub": mock_user.username, "user_id": mock_user.id})
+    token = create_access_token(data={"sub": mock_user.id})
     yield {"Authorization": f"Bearer {token}"}
     app.dependency_overrides.clear()
 
diff --git a/tests/api/test_persistence.py b/tests/api/test_persistence.py
index fac2640..d1fb265 100644
--- a/tests/api/test_persistence.py
+++ b/tests/api/test_persistence.py
@@ -17,7 +17,7 @@ def mock_user():
 @pytest.fixture
 def auth_header(mock_user):
     app.dependency_overrides[get_current_user] = lambda: mock_user
-    token = create_access_token(data={"sub": mock_user.username, "user_id": mock_user.id})
+    token = create_access_token(data={"sub": mock_user.id})
     yield {"Authorization": f"Bearer {token}"}
     app.dependency_overrides.clear()
 
diff --git a/tests/test_workflow_history.py b/tests/test_workflow_history.py
index ccc826a..f774f83 100644
--- a/tests/test_workflow_history.py
+++ b/tests/test_workflow_history.py
@@ -25,6 +25,11 @@ def test_full_history_workflow(history_manager):
     assert user is not None
     assert user.display_name == "E2E User"
     
+    # 1.1 Verify get_user_by_id
+    fetched_user = history_manager.get_user_by_id(user.id)
+    assert fetched_user is not None
+    assert fetched_user.username == email
+    
     # 2. Create Conversation
     conv = history_manager.create_conversation(user.id, "nj", "Test Analytics")
     assert conv.id is not None