diff --git a/agent/build_agent.py b/agent/build_agent.py
index 992839b..9599f3e 100755
--- a/agent/build_agent.py
+++ b/agent/build_agent.py
@@ -261,8 +261,9 @@ def _run_checkout_build_background(job_id, repo_url, repo_dir, start_time):
     releases it when the work finishes."""
     def runner():
         try:
-            subprocess.check_call(['git', 'clone', repo_url, repo_dir])
-            install_and_build(repo_dir, job_id, start_time)
+            with app.app_context():
+                subprocess.check_call(['git', 'clone', repo_url, repo_dir])
+                install_and_build(repo_dir, job_id, start_time)
         except Exception as e:
             print(f"Background checkout/build failed for {job_id}: {e}")
             system_status['status'] = "ready"
@@ -278,7 +279,8 @@ def _run_build_background(job_id, project_path, start_time):
     the thread releases it when the build finishes."""
     def runner():
         try:
-            install_and_build(project_path, job_id, start_time)
+            with app.app_context():
+                install_and_build(project_path, job_id, start_time)
         except Exception as e:
             print(f"Background build failed for {job_id}: {e}")
             _clear_progress(job_id)
@@ -444,6 +446,13 @@ def install_and_build(project_path, job_id, start_time):
         return jsonify({"error": f"Error compiling project: {e}"}), 500
 
     dist_path = os.path.join(project_path, "dist")
+    if not any(os.path.isfile(os.path.join(root, f)) for root, _, files in os.walk(dist_path) for f in files):
+        print(f"Error: build for {job_id} reported success but {dist_path} is empty")
+        system_status['status'] = "ready"
+        system_status['running_job'] = None
+        _clear_progress(job_id)
+        return jsonify({"error": f"Build completed but produced no files in {dist_path}"}), 500
+
     system_status['status'] = "ready"
     system_status['running_job'] = None
     _clear_progress(job_id)
@@ -485,7 +494,8 @@ def download_binaries(job_id):
         job_path = os.path.join(TMP_DIR, BUILD_DIR, job_id)
         dist_path = os.path.join(job_path, "dist")
 
-        if not os.path.exists(dist_path):
+        if not os.path.exists(dist_path) or not any(
+                os.path.isfile(os.path.join(root, f)) for root, _, files in os.walk(dist_path) for f in files):
             return jsonify({"error": f"No binaries found for ID: {job_id}"}), 404
 
         # Create a temporary zip file
diff --git a/ctrl/scheduler.py b/ctrl/scheduler.py
index 780888d..7b394a4 100644
--- a/ctrl/scheduler.py
+++ b/ctrl/scheduler.py
@@ -3,6 +3,7 @@ import logging
 import os
 import threading
 import time
+import zipfile
 
 import requests
 
@@ -225,6 +226,12 @@ class Scheduler:
             for chunk in resp.iter_content(chunk_size=8192):
                 f.write(chunk)
 
+        with zipfile.ZipFile(dest) as zf:
+            files = [n for n in zf.namelist() if not n.endswith("/")]
+        if not files:
+            os.remove(dest)
+            raise RuntimeError(f"Worker {worker['url']} returned an empty artifact zip for {worker_job_id}")
+
         db.update_job(job_id, artifacts=[fname])
 
     # ---- logging / status -------------------------------------------------