diff --git a/.github/workflows/verify-packages.yml b/.github/workflows/verify-packages.yml
new file mode 100644
index 000000000..f4ddae28a
--- /dev/null
+++ b/.github/workflows/verify-packages.yml
@@ -0,0 +1,65 @@
+name: Verify Package Builds
+
+on:
+  push:
+
+jobs:
+  verify:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+          cache: 'npm'
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Install tsx globally
+        run: npm install -g tsx
+
+      - name: Get tags older than 6 months
+        id: get_tags
+        run: |
+          TAGS=$(git for-each-ref --sort=-taggerdate --format '%(refname:short) %(taggerdate:iso8601)' refs/tags | \
+            awk -v date="$(date -d '6 months ago' +%Y-%m-%d)" '$2 < date {print $1}')
+          echo "tags<<EOF" >> $GITHUB_OUTPUT
+          echo "$TAGS" >> $GITHUB_OUTPUT
+          echo "EOF" >> $GITHUB_OUTPUT
+
+      - name: Verify packages for each tag
+        id: verify_tags
+        run: |
+          set -e
+          mkdir -p results
+          echo "| Tag | Result | Differing Packages |" > results/summary.md
+          echo "|-----|--------|--------------------|" >> results/summary.md
+          echo "Tags to check:"
+          echo "${{ steps.get_tags.outputs.tags }}"
+          for TAG in ${{ steps.get_tags.outputs.tags }}; do
+            echo "\nProcessing tag: $TAG"
+            echo "Checking out $TAG"
+            git checkout $TAG
+            npm ci || { echo "| $TAG | npm ci failed | - |" >> results/summary.md; continue; }
+            echo "Running build-packages.ts for tag: $TAG"
+            DIFFERS_JSON=$(TAG=$TAG npx tsx ./build-packages.ts)
+            echo "build-packages.ts output for $TAG: $DIFFERS_JSON"
+            if [ "$DIFFERS_JSON" != "[]" ]; then
+              # Remove brackets and quotes for markdown table
+              DIFFERS_LIST=$(echo $DIFFERS_JSON | jq -r '. | join(", ")')
+              echo "| $TAG | ❌ Mismatch | $DIFFERS_LIST |" >> results/summary.md
+            else
+              echo "| $TAG | ✅ Match | - |" >> results/summary.md
+            fi
+          done
+          git checkout $GITHUB_SHA # Return to original commit
+
+      - name: Print summary table
+        run: |
+          cat results/summary.md
+
+# continue: check github action status !!!
diff --git a/build-packages.ts b/build-packages.ts
new file mode 100644
index 000000000..14f3749c6
--- /dev/null
+++ b/build-packages.ts
@@ -0,0 +1,90 @@
+#!/usr/bin/env tsx
+
+import * as fs from 'fs';
+import * as path from 'path';
+import { spawnSync } from 'child_process';
+
+const ORIGINAL_DIR = process.cwd();
+const PACKAGES_DIR = path.resolve(ORIGINAL_DIR, 'packages');
+
+// Get all package directories
+const packages = fs.readdirSync(PACKAGES_DIR).filter(item => {
+  const itemPath = path.join(PACKAGES_DIR, item);
+  return fs.statSync(itemPath).isDirectory() && !item.startsWith('.');
+});
+
+// console.debug(`Found ${packages.length} packages to process`);
+
+const NPM_VERSION_TAG = (process.env.NPM_VERSION_TAG || 'latest').replace(/^v/, '');
+
+// Process all packages
+const results = packages
+  .map(dir => {
+    const json = path.join(PACKAGES_DIR, dir, 'package.json');
+    const pkg = JSON.parse(fs.readFileSync(json, 'utf8'));
+
+    if (pkg.private === true) {
+      // console.debug(`Skipping package: ${pkg.name}`);
+      return null;
+    }
+
+    // console.debug(`\nProcessing package: ${pkg.name}`);
+    process.chdir(path.join(PACKAGES_DIR, dir));
+
+    // Run npm publish dry-run
+    const result = spawnSync('npm', ['publish', '--dry-run'], { encoding: 'utf8' });
+    const output = `${result.stdout}\n${result.stderr}`;
+
+    // Extract values using inline functions
+    const shasum = extractFromOutput(output, /npm notice shasum:\s+([a-f0-9]{40})/);
+    const integrity = extractFromOutput(
+      output,
+      /npm notice integrity:\s+(sha\d+-[A-Za-z0-9+/=]+(?:\[\.\.\.\][A-Za-z0-9+/=]*==?)?)/
+    );
+
+    // console.debug(`  Package: ${pkg.name}`);
+    // console.debug(`  Tarball hash: ${integrity}`);
+    // console.debug(`  Shasum: ${shasum}`);
+
+    const registryUrl = `https://registry.npmjs.org/${pkg.name}/${NPM_VERSION_TAG}`;
+    const registryCheck = spawnSync('curl', [registryUrl], {
+      encoding: 'utf8',
+    });
+    const registryData = JSON.parse(registryCheck.stdout);
+    const registryShasum = registryData.dist?.shasum;
+
+    return {
+      name: pkg.name,
+      tarballHash: integrity,
+      shasum,
+      differs: registryShasum === shasum,
+    };
+  })
+  .filter(Boolean) as (PackageInfo & { differs: boolean })[];
+
+// Restore original directory
+process.chdir(ORIGINAL_DIR);
+
+// Output final results
+// console.debug('\n=== PACKAGE BUILD RESULTS ===');
+// console.debug(results);
+
+// Output JSON array of differing packages
+const differingPackages = results.filter(r => r.differs).map(r => r.name);
+console.log(JSON.stringify(differingPackages));
+
+// HELPERS
+function extractFromOutput(output: string, regex: RegExp): string {
+  return (
+    output
+      .split('\n')
+      .map(line => line.match(regex)?.[1])
+      .find(Boolean) || 'Not found'
+  );
+}
+
+interface PackageInfo {
+  name: string;
+  tarballHash: string;
+  shasum: string;
+}