This discussion around RCA / UHPO state aggregation is very interesting.
In our research group we have been exploring a related approach for modeling continuous-state UTXO machines without consensus covenants, by moving the enforcement to the signing layer.
The architecture we are experimenting with encodes the evolving state algebraically into a Taproot key tweak (what we call the Astrolabe pattern), while a local Simplicity VM evaluates the covenant logic before a Schnorr signature is produced.
In other words, the covenant is enforced client-side at signing time rather than by the network.
Obviously this does not provide the same trust model as consensus covenants or ANYPREVOUT, but it allowed us to experiment with continuous-state machines (CDPs, AMMs, etc.) on signet/mainnet without pre-signing large transaction trees.
I’m curious whether something like this could be useful as a research testbed for Braidpool-style payout orchestration before consensus primitives are available.
Would a “soft covenant” approach at the signing layer provide any useful insights for RCA/UHPO design, or do you see fundamental limitations that would make it irrelevant for this class of protocol?