At-Most-Once Delivery
The Internet Computer guarantees that messages are delivered at most once: a message may succeed once, reject before running, or run and fail, but the system will not duplicate it. This is the foundation of message semantics on the IC and the reason Sector9 code should treat every await as a possible failure point.
Trap Behavior
When execution fails, the Internet Computer rolls back uncommitted state changes and cancels pending outgoing messages from the current uncommitted segment. Understanding trap behavior is essential for writing robust actors.
Cycles and Resources
Cycles are the computational currency of the Internet Computer. Every operation your canister performs costs cycles, and cycle exhaustion is a runtime resource concern outside Sector9's proof model.