diff --git a/build.sh b/build.sh
index 4ff410d67..06c90dfcf 100755
--- a/build.sh
+++ b/build.sh
@@ -24,6 +24,7 @@ if [ -n "${TEAMCITY_VERSION:-}" ]; then
   source "$VENV/bin/activate"
   set -u
   pip install -U pip setuptools pyinstaller
+  python set-version.py
 fi
 
 npm install
@@ -75,6 +76,6 @@ if [ -n "${TEAMCITY_VERSION:-}" ]; then
   # it to reliably work and it also seemed difficult to configure. Not proud of
   # this, but it seemed better to write my own.
   pip install PyGithub uritemplate
-  python release-on-tag.py --force
+  python release-on-tag.py
   deactivate
 fi
diff --git a/set-version.py b/set-version.py
new file mode 100644
index 000000000..720e8d7d3
--- /dev/null
+++ b/set-version.py
@@ -0,0 +1,20 @@
+"""Set the package version to the output of `git describe`"""
+
+import json
+import os.path
+import subprocess
+import sys
+
+
+def main():
+    version = subprocess.check_output(['git', 'describe']).strip()
+    package_file = os.path.join('app', 'package.json')
+    with open(package_file) as fp:
+        package_data = json.load(fp)
+    package_data['version'] = version
+    with open(package_file, 'w') as fp:
+        json.dump(package_data, fp, indent=2, separators=(',', ': '))
+
+
+if __name__ == '__main__':
+    sys.exit(main())