diff --git a/embed/compose/compose.yaml b/embed/compose/compose.yaml
index 932b774c12..c077bc1ecf 100644
--- a/embed/compose/compose.yaml
+++ b/embed/compose/compose.yaml
@@ -303,6 +303,8 @@ services:
       # pause-admission-disk-headroom-mib flag, which has no LaunchDarkly to
       # come from here; orchestrator releases that predate the knob ignore it.
       PAUSE_ADMISSION_DISK_HEADROOM_MIB: "1024"
+      # Grow the build rootfs after build steps so larger code tasks have room.
+      BUILD_ENSURE_FREE_DISK_SPACE: "true"
       BUILD_CACHE_STORAGE_URL: file:///var/lib/e2b/storage/build-cache
       ARTIFACTS_REGISTRY_PROVIDER: Local
       LOCAL_UPLOAD_BASE_URL: http://127.0.0.1:5008
diff --git a/packages/shared/pkg/featureflags/flags.go b/packages/shared/pkg/featureflags/flags.go
index 3ef23710f6..2d1a751405 100644
--- a/packages/shared/pkg/featureflags/flags.go
+++ b/packages/shared/pkg/featureflags/flags.go
@@ -497,7 +497,8 @@ var (
 	ExpirationIndexHealerFlag = NewBoolFlag("expiration-index-healer", true)
 
 	// BuildEnsureFreeDiskSpace grows the rootfs after build steps and before finalize.
-	BuildEnsureFreeDiskSpace = NewBoolFlag("build-ensure-free-disk-space", false)
+	// Embed has no LaunchDarkly instance, so allow it to opt in through the environment.
+	BuildEnsureFreeDiskSpace = NewBoolFlag("build-ensure-free-disk-space", envBoolOr("BUILD_ENSURE_FREE_DISK_SPACE", false))
 )
 
 // envdTimeoutFallbackMs reads ENVD_TIMEOUT (Go duration string, e.g. "10s")