> For the complete documentation index, see [llms.txt](https://zkcross-network-1.gitbook.io/learn.zkcross.network/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://zkcross-network-1.gitbook.io/learn.zkcross.network/security-and-control/fail-closed-behaviour.md).

# Fail-Closed Behaviour

The default behaviour of zkCross under uncertainty is simple: do nothing unsafe.

If the system detects slippage breaches, oracle deviations, settlement mismatches, adapter errors, route validation failures, liquidity disappearance or abnormal network conditions, execution halts.

The system may then:

* block the current run
* log the event
* escalate monitoring
* isolate a route or venue
* pause new actions
* activate emergency containment logic

This fail-closed posture matters even more in cross-chain environments, where hidden ambiguity can compound quickly if a system continues executing under uncertain state.

zkCross is designed to stop first and move only when validity is clear.