diff --git a/build b/build
index 1875b8d..ac900e6 100755
--- a/build
+++ b/build
@@ -908,6 +908,15 @@ PIN_END
 # Sign artifacts + regenerate releases/index.html on stable cuts.
 # Beta cuts produce no public artifact, so nothing to sign or index.
 if [ "$RELEASE_CHANNEL" = "stable" ]; then
+    # Source ZDDC_SIGNING_KEY from ~/.config/zddc-signing/env if it
+    # isn't already in env. Mirrors ~/.bashrc's auto-sourcing pattern
+    # for ~/.config/{codeberg,forgejo,github}/env, but inside the
+    # build script so non-interactive callers (Forgejo runner daemon,
+    # cron, etc.) pick it up without needing systemd EnvironmentFile
+    # or workflow yaml.
+    if [ -z "${ZDDC_SIGNING_KEY:-}" ] && [ -f "$HOME/.config/zddc-signing/env" ]; then
+        . "$HOME/.config/zddc-signing/env"
+    fi
     echo ""
     echo "=== Signing release artifacts ==="
     sign_release_artifacts "$RELEASES_DIR"