diff --git a/crates/graphforge-storage/benches/m6_storage_io.rs b/crates/graphforge-storage/benches/m6_storage_io.rs
index 6ea16331e..84b38c911 100644
--- a/crates/graphforge-storage/benches/m6_storage_io.rs
+++ b/crates/graphforge-storage/benches/m6_storage_io.rs
@@ -102,10 +102,10 @@ fn seed_generation_chain(root: &std::path::Path, delta_count: usize) {
 fn durable_commit(bencher: Bencher) {
     bencher
         .with_inputs(prepared_publication)
-        .bench_local_values(|(root, workspace, request)| {
+        .bench_local_refs(|(root, workspace, request)| {
             let ProjectStageOutcome::Staged(staged) = stage_project_generation_with_graph_tree(
                 root.path(),
-                &request,
+                request,
                 Some(workspace.path()),
             )
             .unwrap() else {
@@ -191,7 +191,7 @@ fn spill_compaction(bencher: Bencher) {
             publish_delta(root.path());
             root
         })
-        .bench_local_values(|root| {
+        .bench_local_refs(|root| {
             let limits = GraphDeltaCompactionLimits::default();
             compact_graph_delta(
                 root.path(),
diff --git a/scripts/ci/check-m6-benchmarks.py b/scripts/ci/check-m6-benchmarks.py
index fed85b93d..431ffbaf6 100644
--- a/scripts/ci/check-m6-benchmarks.py
+++ b/scripts/ci/check-m6-benchmarks.py
@@ -42,6 +42,22 @@
     print("missing M6 benchmarks: " + ", ".join(missing), file=sys.stderr)
     raise SystemExit(1)
 
+walltime_source = (ROOT / "crates/graphforge-storage/benches/m6_storage_io.rs").read_text(
+    encoding="utf-8"
+)
+for name in ("durable_commit", "spill_compaction"):
+    function = re.search(
+        rf"(?ms)^fn\s+{re.escape(name)}\s*\([^)]*\)\s*\{{(.*?)(?=^#\[divan::bench|\Z)",
+        walltime_source,
+    )
+    if function is None:
+        raise SystemExit(f"cannot inspect TempDir-backed benchmark {name}")
+    body = function.group(1)
+    if ".bench_local_refs(" not in body or ".bench_local_values(" in body:
+        raise SystemExit(
+            f"{name} must keep TempDir teardown outside the timed region with bench_local_refs"
+        )
+
 workflow = WORKFLOW.read_text(encoding="utf-8")
 walltime_job = workflow.split("  m6-walltime:\n", 1)
 if len(walltime_job) != 2: