Smart Contract Demonstration / Developer Tools

UTXO Engineer has published The Covenant Faucet, a live BSV Blockchain mainnet demonstration showing how a transaction output can enforce rules governing how it may be spent.

Each faucet consists of a single UTXO locked behind an OP_PUSH_TX covenant. Rather than assigning control only to a particular keyholder, the script examines the spending transaction and permits movement only when the transaction recreates the required output with a fixed reduction. The person constructing a valid transaction may claim the difference.

The live page shows three implementations of the same basic mechanism: OP_SPLIT, Chronicle with OP_SUBSTR, and Compact + Escape. Each begins with a declining pool, while the public interface displays the remaining balance, claimed transactions, remaining steps, current status, and transaction ancestry directly from the chain.

The example begins with 10,000 satoshis and requires each valid transaction to recreate the controlled output with a 1,100-satoshi reduction. Of that amount, 1,000 satoshis can be claimed by the participant, while 100 satoshis is reserved for the transaction fee. The process continues until the remaining value is too small to satisfy another valid step.

OP_PUSH_TX is a Bitcoin Script technique that allows a locking script to inspect and enforce conditions involving the transaction attempting to spend it. This can include requirements concerning transaction outputs, values, scripts, sequence data, and other transaction properties. (hub.bsvblockchain.org)

UTXO Engineer also documents an unsuccessful version built against a deprecated Chronicle opcode implementation. That attempt left 10,000 satoshis locked in a script that the current node software would not accept, providing a practical reminder that developers must verify the exact output produced by evolving tools and compiler environments.

The faucet page connects the demonstration to broader covenant uses, including scheduled allowances, unavoidable royalty outputs, and transaction-linked objects whose state must continue according to defined rules.

BSV TIMES read:
The Covenant Faucet is valuable because it makes covenant behavior visible through a small, understandable application. The central idea is not the reward itself, but that the network can enforce how a UTXO continues from one transaction to the next. That creates possibilities for applications in which spending conditions, recurring obligations, state transitions, and transaction structure are governed directly by Bitcoin Script rather than by a separate application database or trusted backend.

Posted on July 15, 2026