ci: confirm expected autogenerated reference exists

.gitattributes

@@ -0,0 +1 @@
+docs/reference/**/*.html linguist-generated=true

.github/workflows/ci-build.yml

@@ -28,6 +28,7 @@ jobs:
     env:
       CI_LARGE_SOCKET_MODE_PAYLOAD_TESTING_DISABLED: "1"
       FORCE_COLOR: "1"
+      LATEST_PYTHON_VERSION: "3.13"
     steps:
       - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
         with:
@@ -53,6 +54,14 @@ jobs:
           pip install "SQLAlchemy>=1.4,<2"
           PYTHONPATH=$PWD:$PYTHONPATH pytest tests/slack_sdk/oauth/installation_store/test_sqlalchemy.py
           PYTHONPATH=$PWD:$PYTHONPATH pytest tests/slack_sdk/oauth/state_store/test_sqlalchemy.py
+      - name: Confirm expected autogenerated reference exists
+        if: startsWith(matrix.python-version, env.LATEST_PYTHON_VERSION)
+        run: |
+          python -m venv .venv
+          source .venv/bin/activate
+          bash ./scripts/generate_api_docs.sh
+          git diff
+          git diff --quiet
       - name: Upload test results to Codecov
         if: ${{ !cancelled() }}
         uses: codecov/test-results-action@47f89e9acb64b76debcd5ea40642d25a4adced9f # v1.1.1
@@ -62,7 +71,7 @@ jobs:
           token: ${{ secrets.CODECOV_TOKEN }}
           verbose: true
       - name: Upload test coverage to Codecov (only with latest supported version)
-        if: startsWith(matrix.python-version, '3.13')
+        if: startsWith(matrix.python-version, env.LATEST_PYTHON_VERSION)
         uses: codecov/codecov-action@5a1091511ad55cbe89839c7260b706298ca349f7 # v5.5.1
         with:
           token: ${{ secrets.CODECOV_TOKEN }}