diff --git a/scripts/release.sh b/scripts/release.sh
index f743e7e..9d45cb0 100755
--- a/scripts/release.sh
+++ b/scripts/release.sh
@@ -23,12 +23,35 @@ set -eu
 # exactly what this ~30-line version replaces.
 
 CHANGELOG="CHANGELOG.md"
+BASE="main"
 
 if ! command -v code >/dev/null 2>&1; then
     echo "Error: 'code' (VS Code CLI) not found; install it or remove the editor step." >&2
     exit 1
 fi
 
+# Releases are cut from `main` (see CONTRIBUTING § Publishing workflow). Make
+# that explicit rather than relying on pubv's default-branch check, so the
+# error names `main` even when the remote's default is configured differently.
+CURRENT=$(git symbolic-ref --quiet --short HEAD || true)
+if [ "${CURRENT}" != "${BASE}" ]; then
+    echo "Error: releases are cut from '${BASE}', but HEAD is '${CURRENT:-detached}'." >&2
+    exit 1
+fi
+
+# pubv decides the "default branch" by reading the *local*
+# `refs/remotes/origin/HEAD`, not by asking the remote, and `git fetch` never
+# updates that ref. After a default-branch change — or a clone from when the
+# default was different — it goes stale and pubv warns/fails because the
+# current branch (main) does not match it, even though main *is* the remote
+# default. Refresh it from the remote first, so pubv's branch preflight
+# compares against reality. (Without a network this fails, but so would the
+# push pubv is about to do, so it is a real error rather than one to swallow.)
+if ! git remote set-head origin --auto >/dev/null 2>&1; then
+    echo "Error: could not refresh origin/HEAD; check connectivity to origin." >&2
+    exit 1
+fi
+
 echo "Running pubv..."
 pubv --no-tag --no-push --tag-prefix=none