dsh-restart-app

A restart button in the DeepSeek Harness title strip, just right of the sidebar toggle. One click stops the whole desktop application — Electron shell, Host, renderers, tool subprocesses — and starts it again, then reloads the page into the fresh instance.

Built for the packaged Windows desktop app. On any other Host (dsh web, dsh tui, a plain Node process) the button hides itself: there is nothing to restart, and a browser session must never be able to kill its own terminal.

Why a plugin instead of Alt+F4

Reloading the page is not enough when the Host is wedged: the Host owns the session, the tool subprocesses and the plugin state. Restarting it by hand means finding the right window, quitting, waiting, and reopening — and on Windows the application leaves a tree of DeepSeek Harness.exe children behind if you only close one of them.

This plugin restarts the application from the inside, which lets it stop every process of the application and none of the others.

Install

From this repository:

dsh plugin --profile desktop add github:7AAAAAH/dsh-restart-app

From a checkout:

dsh plugin --profile desktop add link:C:\path\to\dsh-restart-app

A link: install is treated as local development by the plugin manager: it is labelled local and never updates itself. Install from github: (or from npm, once the package is published) to get the released source and update checks.

Then restart the application once so the profile picks the plugin up. From then on the button lives in the top-left strip, right of the sidebar toggle.

Uninstall:

dsh plugin --profile desktop remove dsh-restart-app

Where the button sits

The button is a glyph in the window's top-left strip, immediately right of the sidebar toggle. It registers into shell.overlay rather than the sidebar foot: the foot is hidden while the sidebar is collapsed, and the sidebar package's shell.leading seat is only rendered on macOS. shell.overlay is a full-window layer whose direct children get pointer-events: auto, so an absolutely positioned button there sits in the titlebar without disturbing the layout.

The application's own menu strip starts at --dsh-windows-menu-start (48px) — exactly where the button goes — so the plugin's stylesheet pushes that variable to the right of the button: 84px normally, 120px while the sidebar is collapsed (the collapsed layout parks its new-session button at 48px, so the button itself moves to 84px there). The rules repeat the data-windows-titlebar attribute to outrank the sidebar package's own :has() rule, which would otherwise slide the menu back under the button.

What one click does

1. POST /dsh-restart-app/restart → the Host answers 202 immediately.
2. The Host writes two PowerShell scripts under %TEMP%\dsh-restart-app\<stamp>\ and starts the stage.
3. The stage Start-Processes the real helper and exits, so the helper has no live ancestor left inside the application by the time the application dies.
4. The helper waits 900 ms (long enough for the HTTP response to flush), stops every process whose image name is the application's or whose executable lives under the application directory, waits for the process table to clear, and starts the executable again with Start-Process.
5. Five seconds later it records whether the new application survived, then exits.
6. The page polls its own origin once a second. It waits for the server to go down and come back before reloading: the helper sleeps before it kills anything, so an early successful probe is still the old process.

The helper's log is the first place to look when something goes wrong:

%TEMP%\dsh-restart-app\<stamp>\helper.log

2026-10-23T17:59:01.7560041+08:00 helper start pid=21416
2026-10-23T17:59:03.0707319+08:00 stopping 1 application process(es): 25428
2026-10-23T17:59:03.3103882+08:00 application processes are gone
2026-10-23T17:59:03.8181757+08:00 relaunching C:\Program Files\DeepSeek Harness\DeepSeek Harness.exe
2026-10-23T17:59:03.9243984+08:00 relaunched pid=24200
2026-10-23T17:59:08.9546037+08:00 relaunched application is alive after 5s (pid=24200)
2026-10-23T17:59:08.9556013+08:00 helper done

The two things that make this hard on Windows

Surviving the kill. The helper cannot be a child of the Host: stopping the Host's tree would stop the helper too. A Node detached: true spawn and a stdio: 'ignore' spawn are both reaped at once on this platform (the child exits 0 and does nothing). What does work is an ordinary child that Start-Processes the helper and exits — a helper whose parent is already gone is not part of anybody's tree.

Inheriting a usable environment. The relaunched application must start with the environment the user started it with. The first version of this plugin wrote that environment to a JSON file and rebuilt it in PowerShell; that is a trap. PowerShell 5.1 decodes a BOM-less file as the ANSI code page, so a PATH with a non-ASCII directory either turns into mojibake or makes ConvertFrom-Json throw — after EnvironmentVariables.Clear(), which leaves the application with an empty environment. With no TEMP, the Electron shell resolves its own native-addon cache against os.tmpdir(), which is then the literal relative path undefined\temp, and the Host dies before it is ready:

dsh: host preparation failed: No usable native binding found for
node-addon-require-builtin-win32-x64-msvc (auto)

So the helper never copies the environment: it already has it (Host → helper), and all it does is delete the two markers that would make the shell behave like a Node runtime (ELECTRON_RUN_AS_NODE, DSH_DESKTOP_NODE_EXECUTABLE). It also falls back to a sane TEMP if one is ever missing, because that single missing variable is the difference between a working app and that crash dialog.

Layout

test/ ships with the repository, not with the package: run the assertions from a checkout, not from node_modules.

node test/render.mjs

Requirements

• Windows 10/11, the packaged DeepSeek Harness desktop app.
• PowerShell 5.1 (present on every supported Windows).
• Node 20+ for the Host side.

License

MIT