diff --git a/codebuild/buildspec.yml b/codebuild/buildspec.yml
index 2e9e8d6..37dd6dc 100644
--- a/codebuild/buildspec.yml
+++ b/codebuild/buildspec.yml
@@ -46,6 +46,9 @@ phases:
   pre_build:
     on-failure: ABORT
     commands:
+      - TF_WORKSPACE="${TF_WORKSPACE:-default}"
+      - echo "TF_WORKSPACE=${TF_WORKSPACE}"
+      - test -n "$TF_WORKSPACE" || { echo "ERROR: TF_WORKSPACE is empty"; exit 1; }
       - export TF_VAR_github_token="$GITHUB_TOKEN"
       - |
         BACKEND_CONFIG="backend-configs/${TF_WORKSPACE}.tf"