> ## Documentation Index > Fetch the complete documentation index at: https://aspect.build/llms.txt > Use this file to discover all available pages before exploring further. # Ratchet Mechanism > Use a Bazel ratchet mechanism in CI to lock in invariants like type-check fixes so new commits cannot reintroduce previously eliminated build errors. The [ratchet](https://en.wikipedia.org/wiki/Ratchet_mechanism) is a mechanical tool to ensure "no backsliding". Whenever you tighten the semantics of the build, by ensuring some new invariant holds, you should have a ratchet in place to make sure it stays that way For example, if you fix some type-check errors, you should make sure the CI system will mark any subsequent changes red if they re-introduce those type-check errors. Combined with "change one thing at a time" this can give you incredible power to work in a huge codebase. For example if you just introduce one type-check error code at a time, you can fix only those, and use your ratchet to make sure those don't come back. You can then rinse-and-repeat with low risk changes, while ensuring that the system as a whole is eventually converging on the correct behavior. It feels slow, but this is the same as a gear ratio on a bike: you have incredible "mechanical advantage" to move heavy objects at that slow speed.