Ontoplano and Obsidian
Obsidian is a superb place to think in writing: a folder of Markdown files, links between them, a graph, and a plugin for anything. If your notes are the main thing and you want them as plain files forever, that is what it is for.
Ontoplano starts from the other end. The notes live in notebooks, one per subject, and beside them in the same notebook are that subject's tasks, its place in the week, its goals, its shopping and its bills. Notes are Markdown with pictures and links to tasks; the planning is built in rather than assembled from plugins.
The honest trade: Ontoplano's notes are in its database, not a folder of files — exportable, but not something to open in another editor while the app is running. If plain files are the point, Obsidian is the better home. If the notes keep turning into plans, this is.
Notes and plans in one notebook A subject's writing, its tasks and its dates side by side, without a plugin to wire them together.
On every device, from one place It is a server: every device you sign in from sees the same notebooks, and your own instance costs nothing to run.
An assistant can work in it A key tied to one notebook lets an AI assistant read and write that subject and nothing else.
Try the demo — it makes you an account of your own, with a week already in it. Or run it yourself, or [read what else it does](/).