diff --git a/giterated-models/src/object.rs b/giterated-models/src/object.rs
index 3eddac4..4568873 100644
--- a/giterated-models/src/object.rs
+++ b/giterated-models/src/object.rs
@@ -80,8 +80,7 @@ impl<
                 },
                 operation_state,
             )
-            .await
-            .unwrap();
+            .await?;
 
         Ok(serde_json::from_slice(&result).unwrap())
     }
diff --git a/giterated-models/src/settings/operations.rs b/giterated-models/src/settings/operations.rs
index caabcac..853f031 100644
--- a/giterated-models/src/settings/operations.rs
+++ b/giterated-models/src/settings/operations.rs
@@ -40,4 +40,7 @@ impl<O: GiteratedObject> GiteratedOperation<O> for SetSetting {
 }
 
 #[derive(Error, Debug, Serialize, Deserialize, Clone)]
-pub enum SetSettingError {}
+pub enum SetSettingError {
+    #[error("Invalid setting `{0}` on object `{0}`")]
+    InvalidSetting(String, String)
+}
diff --git a/giterated-stack/src/handler/mod.rs b/giterated-stack/src/handler/mod.rs
index 5a2d173..e811325 100644
--- a/giterated-stack/src/handler/mod.rs
+++ b/giterated-stack/src/handler/mod.rs
@@ -123,6 +123,7 @@ impl<P, O, E> HandlerWrapper<P, O, E> {
         F: Fn(&N, &StackOperationState) -> Result<P, OperationError<R>> + Clone + Send + Sync,
         R: std::fmt::Debug + 'static,
         E: Into<OperationError<R>> + 'static,
+        OperationError<R>: From<OperationError<E>> + 'static,
         F: 'static,
         N: 'static,
         P: 'static,
@@ -143,7 +144,7 @@ impl<P, O, E> HandlerWrapper<P, O, E> {
                         let operation_state = operation_state;
                         match (func)(predicate_output, state, operation_state).await {
                             Ok(success) => Ok(success),
-                            Err(_) => todo!(),
+                            Err(err) => Err(err.into()),
                         }
                     }
                     .boxed_local()
diff --git a/giterated-stack/src/stack.rs b/giterated-stack/src/stack.rs
index 015343f..f0d7323 100644
--- a/giterated-stack/src/stack.rs
+++ b/giterated-stack/src/stack.rs
@@ -8,7 +8,7 @@ use giterated_models::error::{GetValueError, IntoInternalError};
 use giterated_models::message::GiteratedMessage;
 use giterated_models::object::NetworkAnyObject;
 use giterated_models::operation::NetworkAnyOperation;
-use giterated_models::settings::{GetSettingError, Setting};
+use giterated_models::settings::{GetSettingError, Setting, SetSettingError};
 use giterated_models::value::{GetValue, GiteratedObjectValue};
 use giterated_models::{
     error::OperationError,
@@ -366,7 +366,8 @@ impl GiteratedStack {
                     object_kind: &object_type,
                     setting_name: &operation.setting_name,
                 })
-                .unwrap();
+                // TODO: Check this
+                .ok_or(OperationError::Operation(serde_json::to_vec(&SetSettingError::InvalidSetting(operation.setting_name.clone(), object_type.clone())).as_internal_error()?))?;
 
             let setting = (setting_meta.deserialize)(operation.value)
                 .as_internal_error_with_context(format!(