diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index f3f2da01..5468894b 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -68,6 +68,10 @@ jobs:
             echo "public directory is empty"
             exit 1
           fi
+          if [ ! -f .BUILD_FINISHED ]; then
+            echo ".BUILD_FINISHED not found"
+            exit 1
+          fi
       - uses: actions/upload-artifact@v4
         with:
           name: build-artifact-${{ github. ref_name }}
diff --git a/.gitignore b/.gitignore
index 096e1f75..35fd7c3f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,3 +5,4 @@ node_modules
 .cache
 public
 tmp.*
+.BUILD_FINISHED
diff --git a/Build/index.ts b/Build/index.ts
index 9b16fba2..a8d67fb3 100644
--- a/Build/index.ts
+++ b/Build/index.ts
@@ -1,5 +1,6 @@
 import process from 'node:process';
 import os from 'node:os';
+import fs from 'node:fs';
 
 import { downloadPreviousBuild } from './download-previous-build';
 import { buildCommon } from './build-common';
@@ -28,6 +29,7 @@ import { buildCloudMounterRules } from './build-cloudmounter-rules';
 import { createSpan, printTraceResult, whyIsNodeRunning } from './trace';
 import { buildDeprecateFiles } from './build-deprecate-files';
 import { cacheGc } from './lib/make-fetch-happen';
+import path from 'node:path';
 
 process.on('uncaughtException', (error) => {
   console.error('Uncaught exception:', error);
@@ -38,6 +40,8 @@ process.on('unhandledRejection', (reason) => {
   process.exit(1);
 });
 
+const buildFinishedLock = path.join(__dirname, '../.BUILD_FINISHED');
+
 (async () => {
   console.log('Version:', process.version);
 
@@ -60,6 +64,10 @@ process.on('unhandledRejection', (reason) => {
 
   const rootSpan = createSpan('root');
 
+  if (fs.existsSync(buildFinishedLock)) {
+    fs.unlinkSync(buildFinishedLock);
+  }
+
   try {
     const downloadPreviousBuildPromise = downloadPreviousBuild(rootSpan);
     const buildCommonPromise = downloadPreviousBuildPromise.then(() => buildCommon(rootSpan));
@@ -97,6 +105,9 @@ process.on('unhandledRejection', (reason) => {
 
     printTraceResult(rootSpan.traceResult);
 
+    // write a file to demonstrate that the build is finished
+    fs.writeFileSync(buildFinishedLock, 'BUILD_FINISHED\n');
+
     // Finish the build to avoid leaking timer/fetch ref
     await whyIsNodeRunning();
     process.exit(0);