diff --git a/refs.h b/refs.h
index 8c8994cb29..d278775e08 100644
--- a/refs.h
+++ b/refs.h
@@ -422,8 +422,12 @@ void warn_dangling_symrefs(FILE *fp, const char *msg_fmt,
 /*
  * Flags for controlling behaviour of pack_refs()
  * PACK_REFS_PRUNE: Prune loose refs after packing
+ * PACK_REFS_AUTO: Pack refs on a best effort basis. The heuristics and end
+ *                 result are decided by the ref backend. Backends may ignore
+ *                 this flag and fall back to a normal repack.
  */
-#define PACK_REFS_PRUNE 0x0001
+#define PACK_REFS_PRUNE (1 << 0)
+#define PACK_REFS_AUTO  (1 << 1)
 
 struct pack_refs_opts {
 	unsigned int flags;
diff --git a/refs/reftable-backend.c b/refs/reftable-backend.c
index 66cdbbdb24..135bd4e268 100644
--- a/refs/reftable-backend.c
+++ b/refs/reftable-backend.c
@@ -1220,7 +1220,10 @@ static int reftable_be_pack_refs(struct ref_store *ref_store,
 	if (!stack)
 		stack = refs->main_stack;
 
-	ret = reftable_stack_compact_all(stack, NULL);
+	if (opts->flags & PACK_REFS_AUTO)
+		ret = reftable_stack_auto_compact(stack);
+	else
+		ret = reftable_stack_compact_all(stack, NULL);
 	if (ret < 0) {
 		ret = error(_("unable to compact stack: %s"),
 			    reftable_error_str(ret));