"Logging requires a real editor. Waystone has one — it just lives in another repo, and that is fine."
The Second-Editor Temptation
Travel logging means writing, and writing means an editor. The obvious move is to build one: a nice markdown box in Waystone, autosave, some formatting. And that is exactly how a domain engine starts drifting into a worse copy of a sibling. A mature editor is not a text box — it is autosave, document history, attachments, undo, input-method handling, and a hundred details somebody already got right. Waystone refuses to build a second one. Prose belongs to Rekindle, the family's writing editor, and Waystone round-trips to it.
The Ownership Split Is Strict
The line is drawn precisely: Waystone is canonical for dates, places, itinerary, routes, reservations, status, decisions, and structured travel facts. Rekindle is canonical for prose bodies and writing history. Send a daily log to Rekindle to write it properly; pull the latest revision back to update the Waystone projection. What crosses the boundary is not a copy of the editor — it is a link: the document's stable ID, its kind, its revision, a content hash, and the last sync time. Filenames and titles are mutable presentation; the stable ID carries identity.
Round Trips Must Detect Divergence
The dangerous part of any two-system round trip is the moment both sides changed. The naive answer — last write wins — silently destroys somebody's work. Waystone's rule is that round-trip sync must detect divergent edits rather than resolve them silently. Better to surface "these two versions disagree, which do you want?" than to quietly pick one and lose the other. Notice the pattern: the same refusal to overwrite that governs plans, breadcrumbs, and baselines shows up again at the sibling boundary. Silent last-write-wins is the cross-repo version of a retrospective rewrite.