Currently, in .ci.yaml, you can set a field presubmit: false, which causes a configuration to run only in postsubmit. It would also be useful to be able to run a configuration only in presubmit. This would allow us to better tailor presubmit feedback to the specific change. For example, presubmit clang-tidy can suggest fixes on a failure, but in postsubmit that wouldn't make sense.

cc @keyonghan