diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 540d1ea..b8bcc63 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -14,5 +14,7 @@ jobs:
       - run: mkdir -p ~/.cache # work around https://github.com/tweag/topiary/issues/740
       - run: git clone https://github.com/rrthomas/topiary ~/topiary && cd ~/topiary && cargo install --path topiary-cli
       - run: |
+          mkdir -p ~/.cache
+          strace -f topiary -v -v -v -v format --language ursa --query ./src/topiary/ursa.scm < ./src/ursa/prelude.ursa
           npm install
           npm run test-all