diff --git a/install/lib-primitives.sh b/install/lib-primitives.sh
index b4234f4..51c6874 100644
--- a/install/lib-primitives.sh
+++ b/install/lib-primitives.sh
@@ -40,7 +40,7 @@ remove_shell_primitive() {
 }
 
 copy_rust_primitive() {
-  local name="$1" crate src dst_root dst
+  local name="$1" crate src dst_root dst sibling
   crate="$(primitive_field "$name" crate)"
   [ -n "$crate" ] || { err "no 'crate' for rust primitive $name"; return 1; }
   src="$KIT_DIR/_primitives/_rust/$crate"
@@ -54,6 +54,15 @@ copy_rust_primitive() {
     mkdir -p "$dst/tests"
     cp -rf "$src/tests/"* "$dst/tests/" 2>/dev/null || true
   fi
+  # v0.21: kei-artifact and future crates reference sibling data dirs via
+  # include_str!("../schemas/*.json") etc. Copy known sibling directories
+  # when present. Whitelist keeps target/, .git/, build artifacts out.
+  for sibling in schemas assets templates fixtures migrations; do
+    if [ -d "$src/$sibling" ]; then
+      mkdir -p "$dst/$sibling"
+      cp -rf "$src/$sibling/"* "$dst/$sibling/" 2>/dev/null || true
+    fi
+  done
   say "  + rust:  $name (crate $crate)"
 }