Configuration and saved state

Jun keeps two files. Preferences live in the settings file, which you edit. State lives in the layout file, which Jun writes.

File	Holds	Default location	Override
`settings.yaml`	language, theme, text size, reading width, Claude Code folders	`~/.config/jun/settings.yaml`	`JUN_SETTINGS_PATH`
`config.json`	projects, perspectives, regions, tabs	`~/Library/Application Support/Jun/config.json`	`JUN_CONFIG_PATH`

Reviews live in reviews/, in the directory of config.json, a file each.

The settings file is described in Settings.
In both overrides, a relative path resolves against the directory Jun was launched from.

What the layout file saves

The projects, in order, with their names and directories, and the selected project.
Each project's perspectives, in order, with their stable IDs and names, and the selected one.
Each perspective's layout:
- its columns, bottom region and side bar, including hidden ones;
- the order of their tabs, and the selected tab;
- the split percentages and the side bar's width.
What tabs show:
- the file a file tab shows: a branch, or a detached worktree's directory, and a path;
- the session a session tab shows;
- what a Diff tab compares.
Global, its visibility, and the Agents view's layout choice.
Which of Global's views show, how they are arranged, and how they share its room.
Whether the project rail is expanded.

Running processes and their output. Every saved terminal tab starts a fresh shell on the next launch; see Terminals.
Closed tabs, scroll offsets, and the window's size and position.
Messages: they last until Jun quits.

Changes save after 300 ms without further changes.
Pending changes are written at once when the window loses focus, hides or closes.
Jun writes a temporary file in the same directory, then replaces the file atomically.
Jun reads the file only at startup. Quit Jun before editing it by hand.
MyGo treats development and packaged builds separately when it keeps Jun to a single instance. Give development builds their own JUN_CONFIG_PATH, so the two do not share one file.

Situation	What Jun does
The file is unreadable, invalid or of an unsupported version	Keeps the file untouched, reports the error, and does not save during that run. Fix the file and restart.
A save fails	Keeps the pending changes, and offers Retry Save or Continue Editing. Continuing pauses retries until the next change or an attempt to quit.
A save fails while quitting	Keeps the window open, with Retry Save, Cancel Quit and Quit Without Saving.
A project's directory is missing	Keeps the project and its layout, and reports the problem when you enter the project.
A terminal's directory is missing	Keeps the tab, with a Retry button.

The layout file is {"version": 4, "layout": …}.
Older files are converted in memory when loaded, and the next save writes version 4:
- Version 1 → 2 keeps the Work and Review perspectives, every tab and region ID, the selections, each tab's project, and hidden layouts.
- Version 2 → 3 gives each perspective a hidden side bar. Terminals in Global move to the end of the first column of their project's current perspective. Agents and Files tabs in columns and bottom regions are dropped, as are version 1's placeholder file tabs.
- Version 3 → 4 says on each view of Global and the side bar whether it shows, rather than whether it is hidden: a view Jun adds later starts hidden. What shows stays the same.
Older versions of Jun cannot load version 4. Quit the previous Jun before running the upgraded app with the same file.
Preferences that earlier versions kept in the layout file (chinese, theme, textSize) move into the settings file on the first start.
Even older files, state.json, settings.json and window-state.json, are left untouched.