Finish-to-start dependency

A finish-to-start dependency (FS) is a task relationship where the blocked task cannot start until its blocker finishes.

It is the default and most common dependency kind — most work happens in a strict sequence, where one step's output is the next step's input. In Kanbai, every dependency you add defaults to finish-to-start unless you choose otherwise, and the dependency-cycle trigger rejects any chain of dependencies (finish-to-start or otherwise) that would loop back on itself, so a project's task graph can never contain a cycle. A task marked Completed while its finish-to-start blocker is still open is a violated dependency — a real, detectable state Kanbai's Gantt lens surfaces rather than hides. Contrast this with start-to-start, where the second task can begin as soon as the first begins rather than waiting for it to finish, or finish-to-finish and start-to-finish, which tie the two tasks' end points instead of their start points. Choosing the right kind matters for scheduling accuracy: marking a task finish-to-start when the real-world relationship is start-to-start makes a project's computed dates more pessimistic than the actual work requires, while the reverse understates how much a delay upstream will ripple.