diff --git a/.github/workflows/pr-boxel-host.yml b/.github/workflows/pr-boxel-host.yml
index 07f7180c05..93e30c1c88 100644
--- a/.github/workflows/pr-boxel-host.yml
+++ b/.github/workflows/pr-boxel-host.yml
@@ -53,6 +53,7 @@ jobs:
           OWN_REALM_URL: https://realms-staging.stack.cards/drafts/
           OTHER_REALM_URLS: https://realms-staging.stack.cards/published/
           RESOLVED_BASE_REALM_URL: https://realms-staging.stack.cards/base/
+          MATRIX_URL: https://matrix-staging.stack.cards
           S3_PREVIEW_BUCKET_NAME: boxel-host-preview.stack.cards
           AWS_S3_BUCKET: boxel-host-preview.stack.cards
           AWS_REGION: us-east-1