diff --git a/ventures/havre/tools/open.sh b/ventures/havre/tools/open.sh
index 74efd73..9cff705 100644
--- a/ventures/havre/tools/open.sh
+++ b/ventures/havre/tools/open.sh
@@ -10,6 +10,19 @@ git -C "$src" checkout -q "$OV_REF"
 (cd "$src" && npm ci --silent --no-audit --no-fund >/dev/null && npx vite build --base=/open/ >/dev/null)
 rm -rf open
 cp -R "$src/dist" open
+# Havre's key, handed to openvenice: same origin, so it's only a copy between two storage slots in this browser
+cat > open/havre-key.js <<'EOF'
+(function () {
+  try {
+    if (sessionStorage.getItem("venice-auth")) return;
+    var raw = sessionStorage.getItem("havre.key") || localStorage.getItem("havre.key");
+    var key = raw ? JSON.parse(raw) : "";
+    if (typeof key === "string" && key) sessionStorage.setItem("venice-auth", key);
+  } catch (e) { /* no key then */ }
+})();
+EOF
+sed -i.bak 's|<head>|<head><script src="/open/havre-key.js"></script>|' open/index.html && rm -f open/index.html.bak
+grep -q havre-key.js open/index.html
 cat > open/LICENSE.txt <<EOF
 openvenice by nikshepsvn, MIT License: https://github.com/nikshepsvn/openvenice
 Built into Havre at /open/ from commit $OV_REF, unchanged.