Hi, i generated OpenAPI spec file using this method : https://www.meziantou.net/generate-openapi-specification-at-build-time-from-the-code-in-asp-net-core.htm Now i wanted to publish it to pacftlow as a provider pact. How i can achieve this ? Currently i have following errors:

You don't use the usual pact publish command, you use the Pactflow publish provider contract command

its bit not clear for me whats the purpose and how to achievie step 2

The point is that you should test it to your satisfaction. You can use whatever tool, process or otherwise that you deem sufficient

So for example it can be even integration tests written in .net which are producing some results and those should be uploaded together with OAS spec

yep, that’s one option