Yeah! So there are two levels to my validation.

1) I've built the engine and tested it based on CPA or externally reviewed real returns. You can see that in the scenario tests

2) I also have a mechanism for people to test the engine against their previous returns privately and then send bug reports of something wrong

The engine currently only works for 2025 because the 2026 documents aren't out yet from the irs.

There is also definitely a place as well in the tax world for general estimates. For example calculating the tax consequences of a stock sale or iso exercise can get really complicated without a system and cost $800+ with a CPA to do.