A little similar to https://github.com/buildkite/feedback/issues/229 however the targeting would be based on the buildkite agent version. Perhaps this is available already… I couldn’t see it.
In your steps you could have:
agent: version: '>3.0'
You don’t need to define any tags when you start the agent. They’re already built in.
You could combine
agent: queue: 'ruby' version: '^3.0'
This is useful if we use plugins but still have some agents ‘~2.0’