We have ways to approximate our impact on code quality, because we track:

- Change in number of revisions made between open and merge before vs. after greptile

- Percentage of greptile's PR comments that cause the developer to change the flagged lines

Assuming the author is will only change their PR for the better, this tells us if we're impacting quality.

We haven't yet found a way to measure absolute quality, beyond that.

Might be harder to track but what about CFR or some other metric to measure how many bugs are getting through review before versus after the introduction of your product?

You might respond that ultimately, developers need to stay in charge of the review process, but tracking that kind of thing reflects how the product is actually getting used. If you can prove it helps to ship features faster as opposed to just allowing more LOC to get past review (these are not the same thing!) then your product has a much stronger demonstrable value.