diff --git a/.github/actions/configure_dbt_environment/action.yaml b/.github/actions/configure_dbt_environment/action.yaml
index b9415701b..89bbf7eae 100644
--- a/.github/actions/configure_dbt_environment/action.yaml
+++ b/.github/actions/configure_dbt_environment/action.yaml
@@ -5,7 +5,17 @@ runs:
   steps:
     - name: Configure dbt environment
       run: |
-        if [[ $GITHUB_REF_NAME == 'master' ]]; then
+        # GITHUB_REF_NAME is only set on pull_request events, so if it's
+        # present, we must be in a PR context. Use the +x param expansion:
+        # https://stackoverflow.com/a/13864829
+        if [-z ${GITHUB_REF_NAME+x} ]; then
+          echo "On pull request branch, setting dbt env to CI"
+          {
+            echo "TARGET=ci";
+            echo "CACHE_KEY=$GITHUB_HEAD_REF";
+            echo "HEAD_REF=$GITHUB_HEAD_REF"
+          } >> "$GITHUB_ENV"
+        elif [[ $GITHUB_REF_NAME == 'master' ]]; then
           echo "On master branch, setting dbt env to prod"
           {
             echo "TARGET=prod";
@@ -19,11 +29,7 @@ runs:
             echo "HEAD_REF=data-catalog";
           } >> "$GITHUB_ENV"
         else
-          echo "On pull request branch, setting dbt env to CI"
-          {
-            echo "TARGET=ci";
-            echo "CACHE_KEY=$GITHUB_HEAD_REF";
-            echo "HEAD_REF=$GITHUB_HEAD_REF"
-          } >> "$GITHUB_ENV"
+          echo "CI context did not match any of the expected environments"
+          exit 1
         fi
       shell: bash