Yep! I ended up doing my entire co-op with them, and it meshed really well with my interest in creating developer-focused tooling and automation.

Unfortunately I didn't have the time to make the necessary changes and get approval from legal to open-source it, but I spent a good few months creating a tool for validating constraints for deployments on a Kubernetes cluster. It basically lets the operations team specify rules to check deployments for footguns that affect the cluster health, and then can be run by the dev-ops teams locally or as a Kubernetes operator (a daemon service running on the cluster) that will spam a Slack channel if a team deploys something super dangerous.

The neat part was that the constraint checking logic was extremely powerful, completely customizable, versioned, and used a declarative policy language instead of a scripting language. None of the rules were hard-coded into the binary, and teams could even write their own rules to help them avoid past deployment issues. It handled iterating over arbitrary-sized lists, and even could access values across different files in the deployment to check complex constraints like some value in one manifest didn't exceed a value declared in some other manifest.

I'm not sure if a new tool has come along to fill the niche that mine did, but at the time, the others all had their own issues that failed to meet the needs I was trying to satisfy (e.g. hard-coded, used JavaScript, couldn't handle loops, couldn't check across file boundaries, etc.).

It's probably one of the tools I'm most proud of, honestly. I just wish I wrote the code better. Did not have much experience with Go at the time, and I really could have done a better job structuring the packages to have fewer layers of nested dependencies.