The documentation is very generic, with few examples, and a step behind the functionality actually available.
Getting a build to trigger or do certain actions on specific branches or tags seems to be very difficult, and harder to test.
When a commit or tag on a branch is pushed to GIT, it quickly appears in CircleCI - in my case marked as ‘not run’. But it is unclear as to why. There is no further information, the build details page is simply empty.
For example, why does pushing a tagged commit ‘v1.0.0’ get labeled as not run when the circle.yml file starts with the following:
I had this issue as well, with a similar configuration of branches and tags.
Got it to work using this general config, using ignore branches instead of only to achieve. To me it seems like the branches option affects tags as well, but one is not able to configure how.