diff --git a/.github/workflows/publish-release.yml b/.github/workflows/publish-release.yml
index c7e6943fd4..3b8fc5b131 100644
--- a/.github/workflows/publish-release.yml
+++ b/.github/workflows/publish-release.yml
@@ -74,6 +74,20 @@ jobs:
           git config --global user.email "github-actions[bot]@users.noreply.github.com"
           git config --global user.name "github-actions[bot]"
 
+      - name: Check for pre-existing tags
+        run: |
+          SCOPE="${{ steps.meta.outputs.scope }}"
+          VERSION="${{ steps.publish.outputs.version }}"
+          if [ "$SCOPE" == "monorepo" ]; then
+            TAG="v${VERSION}"
+          else
+            TAG="${SCOPE}/v${VERSION}"
+          fi
+          if git rev-parse "$TAG" >/dev/null 2>&1; then
+            echo "ERROR: Tag $TAG already exists" >&2
+            exit 1
+          fi
+
       - name: Create and push git tag
         run: |
           SCOPE="${{ steps.meta.outputs.scope }}"
diff --git a/scripts/release/prerelease.ts b/scripts/release/prerelease.ts
index af81119f0d..45c0b4cb8c 100644
--- a/scripts/release/prerelease.ts
+++ b/scripts/release/prerelease.ts
@@ -76,6 +76,10 @@ function main() {
   console.log("\nBuilding packages...");
   run("pnpm", ["run", "build"]);
 
+  // Run tests before publishing
+  console.log("\nRunning tests...");
+  run("pnpm", ["run", "test"]);
+
   // Publish each package
   console.log("\nPublishing packages...");
   for (const p of getPackagesForScope(scope)) {
diff --git a/scripts/release/publish-release.ts b/scripts/release/publish-release.ts
index 431b3ffef1..f06127784a 100644
--- a/scripts/release/publish-release.ts
+++ b/scripts/release/publish-release.ts
@@ -43,8 +43,17 @@ function getPublishedVersion(packageName: string): string | null {
     encoding: "utf8",
     timeout: 15000,
   });
-  if (result.status !== 0) return null;
-  return result.stdout.trim() || null;
+  if (result.status === 0) {
+    return result.stdout.trim() || null;
+  }
+  // E404 means package doesn't exist on registry — genuinely not published
+  if (result.stderr?.includes("E404") || result.stderr?.includes("is not in this registry")) {
+    return null;
+  }
+  // Any other error (network, auth, rate limit) should stop the release
+  throw new Error(
+    `npm registry check failed for ${packageName}: ${result.stderr?.trim() || "unknown error"}`
+  );
 }
 
 function isGreaterVersion(next: string, current: string): boolean {
@@ -87,7 +96,14 @@ async function main() {
   }
 
   // Safety check: refuse to publish if version isn't greater than what's on npm
-  const published = getPublishedVersion(scopeConfig.versionSource);
+  let published: string | null;
+  try {
+    published = getPublishedVersion(scopeConfig.versionSource);
+  } catch (err: any) {
+    console.error(`Registry check failed — aborting release to avoid publishing over an existing version.`);
+    console.error(err.message);
+    process.exit(1);
+  }
   if (published) {
     console.log(`Currently published version: ${published}`);
     if (!isGreaterVersion(version, published)) {