OP VAULT
OP_VAULT was a proposed pair of Taproot script opcodes defined in BIP 345. Together with CHECKTEMPLATEVERIFY (CTV, BIP 119), the opcodes were intended to give consensus support for vault-style custody. A vault locks coins under a delayed withdrawal path while preserving an always-available recovery path. BIP 345 has BIP status Closed, with BIP 443 (OP_CHECKCONTRACTVERIFY) listed as the proposed replacement. The authors withdrew further advocacy for the vault-specific opcodes in May 2025 in favor of that more general covenant design, which can still express vault constructions.
Vault flow
A typical BIP 345 vault is a Taproot output whose script tree contains at least two leaves. One leaf uses OP_VAULT to authorize a trigger spend. The other uses OP_VAULT_RECOVER to send funds to a predetermined recovery destination. Triggering the vault produces an intermediate output that still carries the recovery leaf and replaces the vault leaf with a timelocked CTV script describing the intended withdrawal. After the relative delay elapses, a withdrawal that matches the CTV template can claim the coins. At any time before that withdrawal confirms, a recovery spend can sweep the funds. BIP 345 never activated on Bitcoin mainnet.
The design assumes Taproot script-path spends and a relative locktime on the withdrawal path so watchers have time to recover stolen or coerced triggers. BIP 345 does not define a complete wallet UX. Application software would still need to track vault outpoints, detect unexpected triggers, and broadcast recovery transactions before the delay expires. Because the BIP is Closed and advocacy moved to BIP 443, new vault-style proposals are expected to compose more general covenant opcodes rather than ship OP_VAULT itself.
CTV (BIP 119) supplies the template commitment for the delayed withdrawal path in the BIP 345 design. Without CTV or an equivalent covenant opcode, the intermediate vault state cannot force the exact withdrawal transaction shape the vault author intended. BIP 443 aims to generalize that contracting surface so vaults become one application among several rather than a dedicated opcode pair.
Status
Prototype tooling and review discussion treated OP_VAULT as unactivated research. No Bitcoin Core release enforces BIP 345. Custody products that market vaults today typically use multisignature policies, pre-signed transaction trees, or sidechain rules rather than mainnet OP_VAULT.
No Bitcoin Core release enforces BIP 345 opcodes. New vault designs are expected to target BIP 443 or other covenant proposals rather than revive OP_VAULT as a dedicated soft fork.