3.4 Miniscript: Writing Wallet Rules Safely

Writing raw Bitcoin Script is risky — a single mistake can lock coins away forever. Miniscript is a friendlier dialect that sits on top of Script and prevents whole categories of bugs.

Wallet developers write spending policies in plain language ('2 of these 3 keys, or 1 key after 6 months of inactivity'), and the wallet automatically compiles that into safe, valid Bitcoin Script. The tooling can even prove the policy makes sense before any coins are deposited.

Practical examples already in real wallets: Liana lets you set up a 'social recovery' where your own key alone can spend, but if you go silent for a year your designated heir's key starts working too. Sparrow uses Miniscript to safely manage advanced multisig and inheritance setups.

Miniscript is mostly invisible to end users — but it's how advanced 'set it and forget it' wallet designs become safe enough for regular people to actually use.