diff --git a/nix/host-modules/hive-c0re/default.nix b/nix/host-modules/hive-c0re/default.nix
index ae2736be..ce89b2fe 100644
--- a/nix/host-modules/hive-c0re/default.nix
+++ b/nix/host-modules/hive-c0re/default.nix
@@ -21,9 +21,33 @@ let
   # only satisfies the ownership guard. libgit2 honours the literal `*`
   # (mid-path globs aren't supported, so per-agent repos can't be listed);
   # in practice these processes only ever touch hyperhive's own repos.
+  #
+  # The agent config inputs now live on the forge
+  # (`git+http://${forge.domain}/agent-configs/<n>.git`, see meta.rs render),
+  # so hive-core's `nix flake update` of those inputs is an authenticated
+  # `git+http` fetch. The `[credential]` stanza points git at the `hive-forge`
+  # helper below (scoped to the forge host) so the fetch authenticates as the
+  # forge `core` user with no token in any URL or lock.
   safeDirGitconfig = pkgs.writeText "hyperhive-safe-gitconfig" ''
     [safe]
     directory = *
+    [credential "http://${config.services.hyperhive.forge.domain}"]
+    helper = hive-forge
+    username = core
+  '';
+
+  # git credential helper for hive-core's authenticated fetches of the
+  # agent-config repos on the forge. Reads the live forge-core admin token
+  # (`/var/lib/hyperhive/forge-core-token` — paths.rs `FORGE_CORE_TOKEN`) on
+  # every invocation, so it never holds a stale copy and survives token
+  # rotation. Scoped to the forge host by the `[credential]` stanza above;
+  # implements the git credential-helper protocol (only `get` answers).
+  forgeCredHelper = pkgs.writeShellScriptBin "git-credential-hive-forge" ''
+    [ "''${1:-}" = "get" ] || exit 0
+    if [ -r /var/lib/hyperhive/forge-core-token ]; then
+      printf 'username=core\n'
+      printf 'password=%s\n' "$(cat /var/lib/hyperhive/forge-core-token)"
+    fi
   '';
 
   # The `hive-c0re serve` config JSON. Keys are snake_case to match the
@@ -116,6 +140,9 @@ in
       after = [ "hive-c0re.socket" ];
       path = [
         pkgs.git
+        # `git-credential-hive-forge` on PATH so git finds it when nix fetches
+        # the forge-hosted agent-config inputs (helper = hive-forge).
+        forgeCredHelper
         "/run/current-system/sw"
       ];
       environment = import ./environment.nix { inherit lib config pkgs; };