the logging is done in rstan. so a fix if needed will have to be there I assume.

there is not unfortunately. I didn't have time to look into it anymore.

can you post a reprex on github?

cool idea! I will think about how to achieve something like this. can you open an issue on GitHub so I don't forget aboht it?

I think this should be documented in the brms_families vignette. perhaps you can double check if the information you are looking for is indeed there.

happy to work with you on that if we find the time :-)

indeed, I saw it at StanCon but I am not sure anymore how production ready the method was.

something like this, yes. but ensuring the positive definiteness of arbitrary constraint correlation matrices is not trivial. so there may need to be some restrictions of what correlation patterns are allowed.

I already thought about this. a complete SEM syntax in brms would support selective error correlations by generalizing set_rescor()