dsh-open-in-app

A DeepSeek Harness (dsh) plugin
for the web UI: a button in the top-right corner of the chat window that
opens the current session's workspace folder with an installed application.
The menu is curated to a whitelist of terminal emulators and popular
IDEs/editors, grouped under "Terminals" and "Editors & IDEs".

Screenshots

The open-in-app control sits in the session header's utility row (top-right
of the chat window), next to the "Session log" button. The folder button
opens the workspace in the app you last chose for it; the chevron opens the
picker menu showing the recently used app, the system default folder handler,
and the whitelisted terminals and editors installed on the host — each with its
app icon:

What it does

• Adds a Codex-style split control to the session header's utility row
  (right side of the chat window header), styled as a pill capsule matching
  the "Session log" header button (32px, 1px border, 18px radius, hover
  fill) with a hairline divider between the two segments:
  • the folder button opens the workspace with one click — in the app
    you last chose for this workspace (remembered per cwd in localStorage,
    its icon shown on the button), falling back to the default editor (the
    most preferred installed editor — VS Code → Cursor → Windsurf → Zed →
    IntelliJ IDEA → … — then the system default);
  • the chevron opens the menu with a pinned "Last used" entry for the
    workspace, a "System default app" entry (the built-in host.openPath
    behavior; Finder on macOS) plus the whitelisted terminals and editors
    installed on the host, each with its app icon (read from the app
    bundle at 32px, delivered as a data: URL; apps whose icon cannot be
    resolved show their name only). The "System default app" row shows the
    default folder handler's real icon (Finder on macOS, File Explorer on
    Windows, the xdg-mime default file manager on Linux), falling back to a
    folder glyph when unresolvable.
• Picking an app from the menu opens the current workspace folder with it:

The whitelist

Matching is case-insensitive against the enumerated app name (.app basename
on macOS, .exe basename on Windows, desktop Name on Linux). Only installed
apps that match appear in the menu.

Terminals — Terminal, iTerm2, Ghostty, Warp, Alacritty, kitty, WezTerm,
Hyper, Tabby, Rio, Contour, Foot, Tilix, Terminator, Konsole, GNOME Terminal,
xterm, mintty, Windows Terminal, PowerShell, Cmder, ConEmu.

IDEs & editors — Visual Studio Code, Cursor, Windsurf, Zed, Xcode, Android
Studio, IntelliJ IDEA, PyCharm, WebStorm, GoLand, CLion, PhpStorm, RubyMine,
Rider, DataGrip, DataSpell, RustRover, Fleet, Aqua, Visual Studio, Eclipse,
NetBeans, Sublime Text, Nova, BBEdit, TextMate, CodeRunner, MacVim, Neovide,
Emacs, Lite XL, HBuilderX.

To add or drop entries, edit the WHITELIST array in lib/apps.js — each
entry is { id, category, match, exact? }, where id is the canonical display
name (also what the native open command must find), match aliases are
substring-tested, and exact aliases are whole-name-tested (used for short
names like code that would otherwise match CodeRunner). Windows JetBrains
launchers (idea64, pycharm64, …) and Code.exe are covered by aliases.

Architecture

• Host half (lib/index.js): a Cordis plugin registering one Typert Remote
  service openInApp (discovered by the Typert Gateway's source-mode fallback —
  no generated TYPERT manifest needed):
  • openInApp/listApps → { apps, defaultIcon? }: whitelisted installed
    apps (with display icons) plus the default folder handler's icon
  • openInApp/openWith(path, appId) → open the folder with one app
  • openInApp/openDefault(path) → open the folder with the system default
  • openInApp/openDefaultEditor(path) → open the folder with the default
    editor (see EDITOR_PRIORITY in lib/apps.js)
• Icons (lib/icons.js): resolves one data:image/* icon per app AND for
  the system default folder handler (Finder / Explorer / xdg-mime default),
  best-effort per platform (see the table above), cached per source path +
  mtime so repeated menu opens are cheap; failures cache as absent, never
  error. On macOS the icns named after the app wins over file-type icns
  (Zed.icns over Document.icns in Zed.app). The enumerated source path
  rides along as a non-enumerable property (lib/apps.js) so JSON transports
  never see it.
• Client half (lib/client.js): a dsh.client web module that mounts the
  Remote endpoints via ctx.remote.$mount(...) and registers
  conversation.session.header.utilities entry open-in-app. The mount runs
  in a nested plugin fiber that declares only remote: the api-gateway
  registers each namespace as a dotted cordis service (remote.openInApp), and
  a fiber that both mounts and injects its own namespace would deadlock the
  loader. Consumption therefore reads the namespace through the documented
  non-strict store access (ctx.reflect.get("remote.openInApp", false)).
• Bundle (cordis.patch.yml): one loader row that activates the host half;
  the profile tooling picks the package up as a profile bundle.

Install

From the directory containing this package:

dsh plugin --profile web add ./dsh-open-in-app

Then restart the web app (dsh web) — the loader and the client module
graph are composed at boot, there is no live reload for newly added plugins.
After the restart, the folder button appears next to the session title and a
menu shows the installed applications.

Security notes

• The Remote endpoints are not in the privileged-method list, so they sit
  behind the same browser-trust fence as the rest of the /api surface
  (loopback / configured trusted hosts only).
• Opening a path spawns a native process on the host. The folder path comes
  from the session's own cwd, which the agent already operates on.
• Icon resolution only reads inside the enumerated app paths (the standard
  application roots) plus the freedesktop icon theme dirs; buffers are capped
  at 256 KB and the native conversions (sips, qlmanage, PowerShell) run
  with an optional abort signal.
• Command failure (open exit codes, missing app) surfaces as an error row in
  the menu instead of throwing.

Development

• lib/apps.js and lib/icons.js are pure Node (no dsh imports) — testable
  standalone (node -e 'import("./lib/icons.js").then(m => m.listAppsWithIcons()).then(console.log)').
• The client bundle must stay self-contained: it only requires the platform
  seed words (react, react/jsx-runtime, @deepseek-ai/dsh-client-ui-primitives).
• To rebuild nothing: there is no build step — lib/ is shipped as-is.