Exploring Wallet-Layer Delegated Signing Semantics (No Consensus Changes)

[Sugarlicks]

I’m drafting a wallet-layer specification for bounded delegated signing authority in Bitcoin (e.g. time-limited delegation, amount-constrained spending, explicit revocation). This operates entirely at the application layer and does not require consensus or BIP changes.

The focus is on expressing delegation constraints explicitly and machine-verifiably within wallet logic rather than relying on key sharing or ad hoc multisig policy design.

Before progressing toward a Rust reference implementation, I’d value perspective on integration considerations within BDK:

Where in the BDK architecture would delegation constraint evaluation most naturally sit?

Are descriptor-based policies already expressive enough for bounded delegation patterns in practice?

Are there existing patterns I should study before going further?

Draft spec and threat model here:
https://github.com/Sugarlicks/silt-identity-core
Sugarlicks/silt-identity-core#1

I’m looking for architectural feedback and constraints, not endorsement.