diff --git a/osbuild/buildroot.py b/osbuild/buildroot.py
index b7940754..317f73aa 100644
--- a/osbuild/buildroot.py
+++ b/osbuild/buildroot.py
@@ -275,6 +275,7 @@ class BuildRoot(contextlib.AbstractContextManager):
 
         # Setup a new environment for the container.
         env = {
+            "container": "bwrap-osbuild",
             "LC_CTYPE": "C.UTF-8",
             "PATH": "/usr/sbin:/usr/bin",
             "PYTHONPATH": "/run/osbuild/lib",
diff --git a/test/mod/test_buildroot.py b/test/mod/test_buildroot.py
index 23f17ff3..849c24be 100644
--- a/test/mod/test_buildroot.py
+++ b/test/mod/test_buildroot.py
@@ -214,6 +214,7 @@ def test_env_isolation(tempdir):
 
     allowed = [
         "_",      # added by `env` itself
+        "container",
         "LC_CTYPE",
         "PATH",
         "PWD",