diff --git a/home-manager/coder.nix b/home-manager/coder.nix
index 0def38941..f2dedd998 100644
--- a/home-manager/coder.nix
+++ b/home-manager/coder.nix
@@ -87,6 +87,10 @@
     persist_dir "$HOME/src/home/.pi/state" "$HOME/.pi/state"
     persist_link "$HOME/src/home/.claude/.credentials.json" "$HOME/.claude/.credentials.json"
 
+    # nix.conf host-specific fragment (private substituters, netrc paths).
+    # Lives in persistent nvme; the main nix.conf `include`s it.
+    persist_link "$HOME/src/home/.config/nix/local.conf" "$HOME/.config/nix/local.conf"
+
     # Coder generates ~/.gitconfig.$COO_CREATOR with work identity and
     # signing key. Homesick's .gitconfig includes ~/.gitconfig.local as the
     # per-machine override — point it at the coder-generated file so the
diff --git a/home/.config/nix/nix.conf b/home/.config/nix/nix.conf
index 42d209cc2..de8d8d60d 100644
--- a/home/.config/nix/nix.conf
+++ b/home/.config/nix/nix.conf
@@ -5,3 +5,7 @@ substituters = https://cache.nixos.org https://nix-community.cachix.org https://
 trusted-public-keys = cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY= nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs= cache.thalheim.io-1:R7msbosLEZKrxk/lKxf9BTjOOH7Ax3H0Qj0/6wiHOgc=
 !include secrets.conf
 netrc-file = /home/joerg/.netrc
+
+# Host-specific fragment (extra substituters, private caches, netrc paths).
+# `include` (soft) — silently skipped on hosts that don't have the file.
+include /root/.config/nix/local.conf