Markwhen is a small, well-considered tool: you write a timeline as markdown, and it renders a Gantt-style view. That’s it. The appeal is that the timeline stays text — diffable, greppable, version-controlled — while giving you the one thing a list of tasks with dates never can: the visual dependency chain.
The reason this matters for project sequencing is that most task apps show you what’s due but not what’s blocking. A task dated Thursday looks like any other Thursday task. But if it’s the thing three other tasks are waiting on, its weight is entirely different, and no flat list will show you that. You need the chain, and you need it cheap enough that you’ll actually draw it.
Markwhen’s bet is that markdown is cheap enough. Write the sequence; see the shape. If a timeline tool is heavy enough that you avoid opening it, it has failed at the only job it had. This one stays out of the way.
Not for every project. But when the sequence is the thing — a launch, a migration, a multi-step setup — a flat list is the wrong data structure, and a markdown timeline is a surprisingly honest one.