diff --git a/tools/publish.sh b/tools/publish.sh
index a4d57dbf..f0f4b614 100755
--- a/tools/publish.sh
+++ b/tools/publish.sh
@@ -21,7 +21,9 @@ bail() {
 
 version="${1:?}"
 version="${version#v}"
-tag="v${version}"
+tag_prefix="v"
+tag="${tag_prefix}${version}"
+changelog="CHANGELOG.md"
 if [[ ! "${version}" =~ ^[0-9]+\.[0-9]+\.[0-9]+(-[0-9A-Za-z\.-]+)?(\+[0-9A-Za-z\.-]+)?$ ]]; then
     bail "invalid version format '${version}'"
 fi
@@ -38,44 +40,55 @@ if gh release view "${tag}" &>/dev/null; then
     bail "tag '${tag}' has already been created and pushed"
 fi
 
-if ! git branch | grep -q '\* main'; then
+if ! git branch | grep -q '\* main$'; then
     bail "current branch is not 'main'"
 fi
 
-tags=$(git --no-pager tag)
+release_date=$(date -u '+%Y-%m-%d')
+tags=$(git --no-pager tag | (grep -E "^${tag_prefix}[0-9]+" || true))
 if [[ -n "${tags}" ]]; then
-    # Make sure the same release does not exist in CHANGELOG.md.
-    release_date=$(date -u '+%Y-%m-%d')
-    if grep -Eq "^## \\[${version//./\\.}\\] - ${release_date}$" CHANGELOG.md; then
-        bail "release ${version} already exist in CHANGELOG.md"
+    # Make sure the same release does not exist in changelog.
+    if grep -Eq "^## \\[${version//./\\.}\\]" "${changelog}"; then
+        bail "release ${version} already exist in ${changelog}"
     fi
-    if grep -Eq "^\\[${version//./\\.}\\]: " CHANGELOG.md; then
-        bail "link to ${version} already exist in CHANGELOG.md"
+    if grep -Eq "^\\[${version//./\\.}\\]: " "${changelog}"; then
+        bail "link to ${version} already exist in ${changelog}"
     fi
-
     # Update changelog.
-    remote_url=$(grep -E '^\[Unreleased\]: https://' CHANGELOG.md | sed 's/^\[Unreleased\]: //; s/\.\.\.HEAD$//')
+    remote_url=$(grep -E '^\[Unreleased\]: https://' "${changelog}" | sed 's/^\[Unreleased\]: //; s/\.\.\.HEAD$//')
     before_tag="${remote_url#*/compare/}"
     remote_url="${remote_url%/compare/*}"
-    sed -i "s/^## \\[Unreleased\\]/## [Unreleased]\\n\\n## [${version}] - ${release_date}/" CHANGELOG.md
-    sed -i "s#^\[Unreleased\]: https://.*#[Unreleased]: ${remote_url}/compare/v${version}...HEAD\\n[${version}]: ${remote_url}/compare/${before_tag}...v${version}#" CHANGELOG.md
-    if ! grep -Eq "^## \\[${version//./\\.}\\] - ${release_date}$" CHANGELOG.md; then
-        bail "failed to update CHANGELOG.md"
+    sed -i "s/^## \\[Unreleased\\]/## [Unreleased]\\n\\n## [${version}] - ${release_date}/" "${changelog}"
+    sed -i "s#^\[Unreleased\]: https://.*#[Unreleased]: ${remote_url}/compare/${tag}...HEAD\\n[${version}]: ${remote_url}/compare/${before_tag}...${tag}#" "${changelog}"
+    if ! grep -Eq "^## \\[${version//./\\.}\\] - ${release_date}$" "${changelog}"; then
+        bail "failed to update ${changelog}"
     fi
-    if ! grep -Eq "^\\[${version//./\\.}\\]: " CHANGELOG.md; then
-        bail "failed to update CHANGELOG.md"
+    if ! grep -Eq "^\\[${version//./\\.}\\]: " "${changelog}"; then
+        bail "failed to update ${changelog}"
+    fi
+else
+    # Make sure the release exists in changelog.
+    if ! grep -Eq "^## \\[${version//./\\.}\\] - ${release_date}$" "${changelog}"; then
+        bail "release ${version} does not exist in ${changelog} or has wrong release date"
+    fi
+    if ! grep -Eq "^\\[${version//./\\.}\\]: " "${changelog}"; then
+        bail "link to ${version} does not exist in ${changelog}"
     fi
 fi
 
 # Make sure that a valid release note for this version exists.
 # https://github.com/taiki-e/parse-changelog
+changes=$(parse-changelog "${changelog}" "${version}")
+if [[ -z "${changes}" ]]; then
+    bail "changelog for ${version} has no body"
+fi
 echo "============== CHANGELOG =============="
-parse-changelog CHANGELOG.md "${version}"
+echo "${changes}"
 echo "======================================="
 
 if [[ -n "${tags}" ]]; then
     # Create a release commit.
-    git add CHANGELOG.md
+    git add "${changelog}"
     git commit -m "Release ${version}"
 fi