diff --git a/api/src/error.rs b/api/src/error.rs
index 33fdb75..a020481 100644
--- a/api/src/error.rs
+++ b/api/src/error.rs
@@ -19,6 +19,8 @@ pub enum OreError {
     MaxSupply = 6,
     #[error("The proof does not match the expected account")]
     AuthFailed = 7,
+    #[error("The same boost cannot be applied twice")]
+    DuplicateBoost = 8,
 }
 
 error!(OreError);