dsh-screenshot-chat

A DeepSeek Harness plugin that adds a Screenshot entry to the chat composer's + menu, so a region captured on your Mac lands in the input box as an image attachment.

Features

• One-click region capture — opens the native macOS selection overlay (the same one as ⇧⌘4), and the selected region arrives in the current conversation's composer as an image attachment, ready to send with your next message. Pressing Esc or right-clicking cancels silently.
• Hide-window capture — hover the Screenshot row and a small toggle appears on the right (○ Hide window). Turn it on and the window that is frontmost when you click is hidden first, then the selection overlay appears; when the capture finishes or is cancelled, the window is restored and brought back to the front.
• Mode is remembered — the toggle state is stored in localStorage and survives page reloads. While it is on, the menu item's description also shows the active mode, so you can see it without hovering.
• Platform-aware — the menu entry is hidden automatically on platforms without screencapture (anything other than macOS).

Install

dsh plugin add dsh-screenshot-chat

Then restart DeepSeek Harness (or reload the web client) so the bundle is composed.

Local development

Point a profile at a checkout instead of the published package:

{
  "dependencies": {
    "dsh-screenshot-chat": "link:/absolute/path/to/dsh-screenshot"
  },
  "dsh": { "profile": { "bundles": ["...", "dsh-screenshot-chat"] } }
}

Run pnpm install in the profile. With HMR enabled, config changes apply immediately; otherwise restart DSH. Host-side edits (index.js) take effect after touching the profile's cordis.patch.yml (any change re-composes the tree without a restart); client-side edits (client.js) are hot-replaced by the client HMR poll.

Usage

1. Click + → Screenshot in the composer.
2. Drag to select a region on screen.
3. The capture appears in the composer as an image attachment — send it as usual.

To capture without the DSH window in the shot, hover the menu entry, switch on Hide window, then click Screenshot. The window disappears during selection and comes back afterwards.

Configuration

Override the defaults from your profile patch, keyed by the plugin id:

- id: dsh-screenshot-chat
  name: 'dsh-screenshot-chat'
  config:
    timeoutMs: 180000   # how long the region selection may stay open

How it works

Host side (index.js)

Registers same-origin routes under /.dsh-screenshot on the host web server:

• POST /capture with body { "hide": true | false }
  • Runs screencapture -i -x -o <tempfile>, waits for the selection, then returns the PNG as base64 and deletes the temp file immediately. A cancelled selection returns { cancelled: true }.
  • With hide: true it first resolves the frontmost process name through AppleScript (System Events) and hides it (the equivalent of ⌘H, with a system-level denylist — Finder, Dock, System Settings and friends are never hidden), waits for the hide animation to settle (350 ms), then captures. A finally block restores and re-focuses the window whether the capture succeeded, was cancelled, or timed out.
• GET /health lets the browser half probe platform support (the entry is hidden off macOS).

Only one capture may run at a time. A capture that stays open longer than timeoutMs (default 180 s) is terminated, and osascript calls time out after 60 s.

Browser side (client.js)

Contributes a screenshot command to the + menu through commandUi.register (kind: 'action', so a click runs the current mode). A document-level mouseover delegate spots the menu row carrying the data-dsc-icon marker and mounts the hover toggle inside it, using native listeners and inline styles so it does not depend on the menu component's internal class names. mousedown and click on the toggle stop propagation so the row is not selected.

The returned image is wrapped in a File and handed to conversation.createDrafts plus the composer's addFiles — the exact same attachment path as pasting an image, so previews, size limits, and upload encoding all run through the host's existing logic.

Permissions (macOS)

1. Screen Recording — the first capture may prompt for authorization, or grant it under System Settings → Privacy & Security → Screen Recording for the app running the DSH host. Without it, captures can come out as wallpaper only.
2. Automation (hide-window capture only) — hiding and restoring the window uses System Events, so macOS asks to allow controlling System Events on first use; the same switch lives under System Settings → Privacy & Security → Automation. Denying it leaves plain region capture working; hide-window capture shows an authorization hint instead.

Limitations

• Interactive region selection relies on macOS screencapture -i, so the plugin works on macOS only; the menu entry hides itself elsewhere.
• Capture runs on the Mac hosting the DSH process, not on the machine running the browser. For a local deployment these are the same machine.
• Hide window hides whichever app is frontmost at the moment you click. If you switch to another app immediately after clicking, that app is the one hidden.

License

MIT