diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 19b1001..b408073 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -19,14 +19,15 @@ jobs:
         run: dotnet test
 
       - name: Pack NuGet packages (CI versions)
-        if: startsWith(github.ref, 'refs/heads/')
+        if: startsWith(github.ref, 'refs/heads/') && github.event_name == 'push' && startsWith(github.repository, 'efcore/')
         run: dotnet pack --configuration Release --output nupkgs --version-suffix "ci.$(date -u +%Y%m%dT%H%M%S)+sha.${GITHUB_SHA:0:9}" -p:ContinuousIntegrationBuild=true
 
       - name: Pack NuGet packages (Release versions)
-        if: startsWith(github.ref, 'refs/tags/v')
+        if: startsWith(github.ref, 'refs/tags/v') && github.event_name == 'push' && startsWith(github.repository, 'efcore/')
         run: dotnet pack --configuration Release --output nupkgs -p:ContinuousIntegrationBuild=true
 
       - name: Upload artifacts
+        if: github.event_name == 'push' && startsWith(github.repository, 'efcore/')
         uses: actions/upload-artifact@v1
         with:
           name: EFCore.NamingConventions