diff --git a/src/adapters/asl_derivation_index_fs/asl_derivation_index_fs.c b/src/adapters/asl_derivation_index_fs/asl_derivation_index_fs.c
index 3ce0c64..3f374bc 100644
--- a/src/adapters/asl_derivation_index_fs/asl_derivation_index_fs.c
+++ b/src/adapters/asl_derivation_index_fs/asl_derivation_index_fs.c
@@ -638,21 +638,13 @@ amduat_asl_store_error_t amduat_asl_derivation_index_fs_add(
   }
   *dir_c = '\0';
 
-  if (!amduat_asl_derivation_ensure_directory(artifact_dir) ||
-      !amduat_asl_derivation_ensure_directory(dir_b) ||
-      !amduat_asl_derivation_ensure_directory(dir_a)) {
-    free(path);
-    free(dir_a);
-    free(dir_b);
-    free(artifact_dir);
-    free(artifact_hex);
-    return AMDUAT_ASL_STORE_ERR_IO;
-  }
-
   {
+    char *index_path = NULL;
     char *derivations_path = NULL;
     char *by_artifact_path = NULL;
-    if (!amduat_asl_derivation_build_derivations_path(index->root_path,
+    if (!amduat_asl_derivation_join_path(index->root_path, "index",
+                                         &index_path) ||
+        !amduat_asl_derivation_build_derivations_path(index->root_path,
                                                       &derivations_path)) {
       free(path);
       free(dir_a);
@@ -661,7 +653,9 @@ amduat_asl_store_error_t amduat_asl_derivation_index_fs_add(
       free(artifact_hex);
       return AMDUAT_ASL_STORE_ERR_IO;
     }
-    if (!amduat_asl_derivation_ensure_directory(derivations_path)) {
+    if (!amduat_asl_derivation_ensure_directory(index_path) ||
+        !amduat_asl_derivation_ensure_directory(derivations_path)) {
+      free(index_path);
       free(derivations_path);
       free(path);
       free(dir_a);
@@ -672,6 +666,7 @@ amduat_asl_store_error_t amduat_asl_derivation_index_fs_add(
     }
     if (!amduat_asl_derivation_join_path(derivations_path, "by_artifact",
                                          &by_artifact_path)) {
+      free(index_path);
       free(derivations_path);
       free(path);
       free(dir_a);
@@ -682,6 +677,7 @@ amduat_asl_store_error_t amduat_asl_derivation_index_fs_add(
     }
     if (!amduat_asl_derivation_ensure_directory(by_artifact_path)) {
       free(by_artifact_path);
+      free(index_path);
       free(derivations_path);
       free(path);
       free(dir_a);
@@ -691,9 +687,20 @@ amduat_asl_store_error_t amduat_asl_derivation_index_fs_add(
       return AMDUAT_ASL_STORE_ERR_IO;
     }
     free(by_artifact_path);
+    free(index_path);
     free(derivations_path);
   }
 
+  if (!amduat_asl_derivation_ensure_directory(dir_b) ||
+      !amduat_asl_derivation_ensure_directory(dir_a)) {
+    free(path);
+    free(dir_a);
+    free(dir_b);
+    free(artifact_dir);
+    free(artifact_hex);
+    return AMDUAT_ASL_STORE_ERR_IO;
+  }
+
   err = amduat_asl_derivation_open_records_file(path, &fp);
   if (err != AMDUAT_ASL_STORE_OK) {
     free(path);
diff --git a/tests/asl/test_asl_derivation_index_fs.c b/tests/asl/test_asl_derivation_index_fs.c
index 6ff073d..d45d75d 100644
--- a/tests/asl/test_asl_derivation_index_fs.c
+++ b/tests/asl/test_asl_derivation_index_fs.c
@@ -71,7 +71,7 @@ static amduat_reference_t make_ref(uint8_t seed, size_t len) {
   for (size_t i = 0; i < len; ++i) {
     bytes[i] = (uint8_t)(seed + i);
   }
-  return amduat_reference(0x0001u, amduat_octets(bytes, len));
+  return amduat_reference(0x1234u, amduat_octets(bytes, len));
 }
 
 static int test_round_trip(void) {
@@ -116,15 +116,21 @@ static int test_round_trip(void) {
   record2.has_params_ref = false;
   record2.has_exec_profile = false;
 
-  if (amduat_asl_derivation_index_fs_add(&index, artifact_ref, &record) !=
-      AMDUAT_ASL_STORE_OK) {
-    fprintf(stderr, "add record failed\n");
-    goto cleanup_records;
+  {
+    amduat_asl_store_error_t err =
+        amduat_asl_derivation_index_fs_add(&index, artifact_ref, &record);
+    if (err != AMDUAT_ASL_STORE_OK) {
+      fprintf(stderr, "add record failed: %d\n", err);
+      goto cleanup_records;
+    }
   }
-  if (amduat_asl_derivation_index_fs_add(&index, artifact_ref, &record2) !=
-      AMDUAT_ASL_STORE_OK) {
-    fprintf(stderr, "add record2 failed\n");
-    goto cleanup_records;
+  {
+    amduat_asl_store_error_t err =
+        amduat_asl_derivation_index_fs_add(&index, artifact_ref, &record2);
+    if (err != AMDUAT_ASL_STORE_OK) {
+      fprintf(stderr, "add record2 failed: %d\n", err);
+      goto cleanup_records;
+    }
   }
 
   if (amduat_asl_derivation_index_fs_list(&index,