diff --git a/.envrc b/.envrc
index d7af17fa..1131ac80 100644
--- a/.envrc
+++ b/.envrc
@@ -5,3 +5,8 @@ fi
 
 nix_direnv_manual_reload
 use flake . --no-pure-eval --accept-flake-config
+
+# Substrate-backed model/dataset cache (anvil-dev only) — keeps
+# vm-devs rootfs slim and shares the cache with vm-runner CI.
+# HF_HOME is already exported globally via PAM session vars.
+[[ -d /srv/anvil/caches ]] && export MAT_VIS_CACHE=/srv/anvil/caches/mat-vis