diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 43c96dbd16..1ac9c2b944 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -93,7 +93,7 @@ jobs:
         run: python -m downloads.preload setupcfg_examples.txt
       - name: Install tox
         run: |
-          python -m pip install tox
+          python -m pip install tox 'pyproject-api<1.6.0'  # workaround #4031
       - name: Run
         run: tox
       - name: Create coverage report
@@ -120,7 +120,7 @@ jobs:
         uses: actions/setup-python@v4
       - name: Install tox
         run: |
-          python -m pip install tox
+          python -m pip install tox 'pyproject-api<1.6.0'  # workaround #4031
       - name: Run
         run: tox
 
@@ -220,7 +220,7 @@ jobs:
           python-version: "3.10"
       - name: Install tox
         run: |
-          python -m pip install tox
+          python -m pip install tox 'pyproject-api<1.6.0'  # workaround #4031
       - name: Run integration tests
         run: tox -e integration
 
@@ -240,7 +240,7 @@ jobs:
           python-version: 3.x
       - name: Install tox
         run: |
-          python -m pip install tox
+          python -m pip install tox 'pyproject-api<1.6.0'  # workaround #4031
       - name: Run
         run: tox -e release
         env: