Wito Delnat

Formal verification never seemed worth it: writing a faithful TLA+ spec took too long. But now agents can write the spec from your code. We tried it on the rebuilt Depot Registry garbage collector, and the model checker found something our tests and reviews didn't: a race that could delete live data.

Speeding up CI isn't one heroic refactor, it's a hunt for the next bottleneck, and for most teams the first one is the test suite. Here's how to attack it with parallelism, sharding, prebuilt images, and a job-density rule that keeps wider sharding from quietly torching your bill.

Depot Registry v2 is a ground-up rewrite of our container registry. The original design worked well as an ephemeral build store, but it had limitations around tags and repository naming. V2 solves those limitations and adds support for using it as a primary registry.