diff --git a/contracts/okp4-cognitarium/src/error.rs b/contracts/okp4-cognitarium/src/error.rs
index 56754195..6220b3aa 100644
--- a/contracts/okp4-cognitarium/src/error.rs
+++ b/contracts/okp4-cognitarium/src/error.rs
@@ -1,4 +1,4 @@
-use cosmwasm_std::StdError;
+use cosmwasm_std::{StdError, Uint128};
 use thiserror::Error;
 
 #[derive(Error, Debug, PartialEq)]
@@ -6,6 +6,36 @@ pub enum ContractError {
     #[error("{0}")]
     Std(#[from] StdError),
 
+    #[error("{0}")]
+    Store(#[from] StoreError),
+
+    #[error("Only the owner can perform this operation.")]
+    Unauthorized {},
+
     #[error("Not implemented.")]
     NotImplemented,
 }
+
+#[derive(Error, Debug, PartialEq)]
+pub enum StoreError {
+    #[error("Maximum triples number exceeded: {0}")]
+    MaxTriplesLimitExceeded(Uint128),
+
+    #[error("Maximum byte size exceeded: {0}")]
+    MaxByteSize(Uint128),
+
+    #[error("Maximum triple byte size exceeded: {0} / {1}")]
+    MaxTripleByteSize(Uint128, Uint128),
+
+    #[error("Maximum query limit exceeded: {0} / {1}")]
+    MaxQueryLimit(Uint128, Uint128),
+
+    #[error("Maximum query variable count exceeded: {0} / {1}")]
+    MaxQueryVariableCount(Uint128, Uint128),
+
+    #[error("Maximum insert byte size exceeded: {0}")]
+    MaxInsertDataByteSize(Uint128),
+
+    #[error("Maximum insert triple count exceeded: {0}")]
+    MaxInsertDataTripleCount(Uint128),
+}