Emergency pause (circuit breaker)

Developers add a pausable switch, often based on standard libraries, and assign it to a guardian: a team multisig, a security council or an automated monitor. When triggered, key functions revert until the switch is lifted, which can stop an ongoing exploit, buy time to deploy a fix or prevent users from interacting with a broken price feed.

Pauses have limited losses in several real incidents, and many lending markets, bridges and stablecoins keep one as standard practice. Some protocols scope them narrowly, for example pausing a single market or only new borrowing, and some layer-1 and layer-2 networks have similar mechanisms at the sequencer or validator level.

The trade-off is centralisation. Whoever holds the pause key can lock user funds, whether by mistake, under legal pressure or after being compromised, and a pause that is too slow does little against an attack that drains a pool in one transaction. Users should check who controls the switch, whether it can only pause or also move funds, and how long a pause can last.