@bitgo/utxo-descriptors

A library for constructing [Bitcoin output descriptors][bip-380] (BIP-380) — descriptor strings that pair on-chain UTXOs with a derivable, parseable key-tracking expression.

This package is the canonical home for descriptor-building logic across BitGo's UTXO codebase. It deliberately stays one layer above [@bitgo/wasm-utxo][wasm-utxo]: that package owns descriptor parsing and miniscript compilation. This package owns the high-level builders that emit valid descriptor strings for the protocols BitGo supports.

Install

yarn add @bitgo/utxo-descriptors

Module layout

src/
├── index.ts                  # re-exports each protocol module under a namespace
└── sbtc/                     # sBTC peg-in deposit descriptors
    ├── constants.ts
    ├── descriptor.ts
    ├── depositAddress.ts
    └── index.ts

Each new protocol gets its own subdirectory under src/ and is re-exported as a namespace from src/index.ts, so consumers import it as import { sbtc } from '@bitgo/utxo-descriptors'.

sBTC

The sbtc namespace builds descriptors for sBTC peg-in deposits — Bitcoin UTXOs whose output script is a Taproot tree with two leaves:

• a deposit leaf, spendable only by the sBTC signers, that commits to the Stacks recipient and the maximum signer fee
• a reclaim leaf, spendable by the depositor after a relative timelock, that lets the depositor recover their BTC if the signers fail to act

Both leaves are expressed as Bitcoin miniscript fragments inside a single tr() descriptor — no raw script bytes, no out-of-band leaf hashing. This is enabled by the payload_drop(<hex>) fragment and tap-context r:older(N) shipped in @bitgo/wasm-utxo 4.11.0 (BitGoWASM #272).