diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 376eccb..6cf583e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -105,9 +105,10 @@ jobs:
           PROTOWIRE_CPP_DIR: ${{ github.workspace }}\protowire-cpp-checkout
         # editable installs don't bundle DLLs — _protowire.pyd resolves
         # libprotobuf.dll / libabsl_*.dll out of vcpkg's bin dir at
-        # import time. Put it on PATH for the pytest run.
+        # import time. Put it on PATH for the pytest run, and vcpkg's
+        # protoc too: the tests that compile a schema skip without it (#43).
         run: |
-          $env:PATH = "$env:VCPKG_INSTALLATION_ROOT\installed\x64-windows\bin;$env:PATH"
+          $env:PATH = "$env:VCPKG_INSTALLATION_ROOT\installed\x64-windows\bin;$env:VCPKG_INSTALLATION_ROOT\installed\x64-windows\tools\protobuf;$env:PATH"
           pytest -v
 
   # ---------------------------------------------------------------------