diff --git a/contracts/Cargo.toml b/contracts/Cargo.toml
index 206e5aa..37c1d4a 100644
--- a/contracts/Cargo.toml
+++ b/contracts/Cargo.toml
@@ -1,3 +1,6 @@
 [workspace]
-members = ["invoice", "settlement"]
+members = [
+    "invoice",
+    "settlement",
+]
 resolver = "2"
diff --git a/contracts/settlement/src/lib.rs b/contracts/settlement/src/lib.rs
index 0892014..dcfc51f 100644
--- a/contracts/settlement/src/lib.rs
+++ b/contracts/settlement/src/lib.rs
@@ -1,6 +1,16 @@
 #![no_std]
 
-use soroban_sdk::{contract, contractimpl, contracttype, contracterror, Address, Env, Vec};
+use soroban_sdk::{contract, contracterror, contractimpl, contracttype, Address, Bytes, Env, Vec};
+
+#[contracterror]
+#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+#[repr(u32)]
+pub enum SettlementError {
+    NotFound = 1,
+    NotPending = 2,
+    InsufficientApprovals = 3,
+    Unauthorized = 4,
+}
 
 #[contracttype]
 #[derive(Clone, Debug, Eq, PartialEq)]