Act

Act runs GitHub Actions workflows locally, replacing the commit–push–wait loop with faster feedback. We mentioned it in our GitHub Actions blip back in 2021. Coding agents give Act new relevance because the growing volume of commits and pushes can cause build contention. Act lets coding agents run a workflow locally before pushing, bringing CI directly into their generative loop and supporting agent pipeline responsibility.

Our teams find that Act handles most GitHub Actions workflow development, although it isn't a perfect replica of the GitHub Actions environment. For example, its default images lack some runner tools, and it doesn’t support concurrency, permissions and environment secrets. Paired with static checking such as zizmor, Act helps coding agents keep the build working when they change the pipeline itself.