diff --git a/kit/build/build-sputnik-with-mjs b/kit/build/build-sputnik-with-mjs
index 2e456b4..54598e5 100755
--- a/kit/build/build-sputnik-with-mjs
+++ b/kit/build/build-sputnik-with-mjs
@@ -5,8 +5,9 @@ set -euo pipefail
 DEPLOY_DIR="$PWD/target/deploy"
 PKG_JSON_DIR="$PWD/target/sputnik"
 
-# Set the path for the developer JS bundle used in the build process.
+# Set the path for the developer JS bundle and RS moduel with custom functions generated by the build process.
 export DEV_SCRIPT_PATH="$DEPLOY_DIR/sputnik.index.mjs"
+export DEV_FUNCTIONS_PATH="$DEPLOY_DIR/sputnik_index.rs"
 
 # Build the Sputnik canister.
 ./kit/build/build-sputnik --pkg-json-dir="$PKG_JSON_DIR" > /dev/null