augmentor-dsh-extension-plugin

Augmentor, powered by DSH

Augmentor turns any DeepSeek Harness (DSH) web session into a browser operator: a Chrome side panel chats with your DSH app, and the agent drives your real browser — live accessibility snapshot, click, type, tab switching — with the user watching every action pulse on the actual page. Chats are real DSH sessions in a dedicated directory, and Save attaches the current chat to a DSH workspace.

┌─ Chromium (MV3 extension) ─────────────────┐   ┌─ Your machine ─────────────────────────────────────────────┐
│ side panel: chat UI (real DSH sessions)    │   │ pipe.mjs — native messaging host (Node, loopback)          │
│ sw.js: native port + browser executor +    │   │  ├─[POST /api/<method>]──────────────▶ running DSH app      │
│  work-tab injection (page veil, overlays)  │   │  ├─[WS /api/events.mux|host]◀───────── downlink frames      │
└──────────────┬─────────────────────────────┘   │  └─[WS <wsPath, from handshake>]──────▶ dsh-augmentor plugin│
               │ native messaging (token-gated)  │        /api handshake + pipe channel + browser tools +     │
               └────────────────────────────────▶│        chat lifecycle (save-to-workspace)                 │
                                                 └────────────────────────────────────────────────────────────┘

No sidecar runtime, no second DSH process: the extension talks to the running DSH app over its stock /api surface (the pipe is the browser's loopback stand-in client, because the extension's Origin is refused by the DSH trust fence — by design).

Components

path	what it is
extension/	MV3 Chrome extension: side panel chat, service worker (native port + browser executor), page veil, work-tab overlays, theme tokens
pipe.mjs	native messaging host: loopback bridge to the DSH app's /api surface, downlinks, plugin channel
plugin/	the dsh-augmentor DSH plugin (npm package + git bundle): /api/augmentor handshake, pipe WS channel, browser_* tools, chat lifecycle
wire.mjs	the shared wire primitives (frame codec + pending table) used by all three runtimes — one implementation, three consumers
install-native-host.sh	installs the Chromium native-messaging-host manifest + the per-machine channel token
test/	e2e suites (m3, sw, panel, chrome, m2, tools) + install-proof.mjs (deterministic fresh-user install proof) + plugin/tests/boot/
PROPOSAL-plugin-architecture.md	the architecture record: milestones M1–M4, audit findings S/D/F, decisions

Install

Prereqs: Node.js (v22.19+ or v24+), a running dsh web instance, a Chromium-based browser (Chrome/Chromium/Edge; Firefox & Safari are "coming soon" — the native-messaging + content-injection stack is Chromium-specific today).

1. Clone

   git clone https://github.com/ManoloRemiddi/augmentor-dsh-extension-plugin.git
   

2. Load the extension — chrome://extensions → Developer mode → Load unpacked → pick the extension/ directory. Note the extension ID.

3. Install the native host

   ./install-native-host.sh <extension-id>
   

   Writes the NMH manifest (points at pipe.mjs), creates the per-machine action-channel token (~/.dsh/augmentor-ws-token, 0600) if missing, and installs the repo's Node dependencies (root + plugin/) if missing.

4. Mount the plugin into your DSH profile

   dsh plugin --profile web add <repo-path>/plugin
   

   (or from npm: dsh plugin --profile web add dsh-augmentor.) Restart the dsh web session so the profile composes the plugin layer.

   pnpm users — first 24h after a release: dsh plugin forwards to pnpm, and pnpm ≥ 11 enforces a ~24h minimum release age (supply-chain protection) — silently installing the newest version that passes. Right after a publish, the bare name can therefore resolve to the previous release. npm view dsh-augmentor version shows the newest; to get it immediately, pin it: dsh plugin --profile web add dsh-augmentor@<version>. The bare name self-heals once the release is a day old.

5. Reload the extension (it reconnects the native port; a brief SW reconnect blip is normal). Open a side panel session, type a prompt, and the agent can now see and drive the active work tab.

Security posture

• The DSH trust fence is why the pipe exists — it is not bypassed. The DSH app's /api refuses requests from foreign browser origins (the extension's chrome-extension:// origin included, by design). pipe.mjs is a loopback stand-in client: it runs locally as the user and talks to the app over 127.0.0.1, which is exactly what the fence permits.
• No new remote surface. Every hop is loopback (extension ↔ pipe via native messaging, pipe ↔ app via 127.0.0.1); nothing this stack adds is reachable from other hosts. The trust boundary is the local OS user: anything that can already read your home directory is not blocked by this stack (and could already do the same things directly against the app).
• The action channel is secret-gated. The browser_* commands flow over a WS channel the plugin authenticates with a per-machine token ($DSH_HOME/augmentor-ws-token, 0600, created by the installer or first boot; a configured actionToken wins). The pipe presents it in the WS handshake header and the plugin compares it in constant time; a local process without that file cannot drive your browser.
• The in-panel "Trust-fence probe" (≣ Sessions → Probe) is a diagnostic that shows the fence working as designed (extension-origin requests refused, loopback requests accepted). It probes; it does not bypass.

Development

# full e2e battery (six suites) — run from the repo root:
cd test && node m3-e2e.mjs && node sw-e2e.mjs && node panel-e2e.mjs \
  && node chrome-e2e.mjs && node m2-e2e.mjs && node tools-e2e.mjs

# plugin boot test:
sh plugin/tests/boot/run.sh

The suites are hermetic: each creates its own marker session (and archives it on cleanup), never touches user sessions, and the live-browser suites (m3, chrome, m2) run against the real local DSH app + a real Chrome profile.

deterministic install proof — the documented journey, end to end, on a fresh

DSH home + fresh Chromium profile (never touches your real ~/.dsh):

node test/install-proof.mjs # clone → boot → plugin → ext → NMH → pipes:1 PROOF_LLM=1 node test/install-proof.mjs # + a real agent drives the headless browser PROOF_SOURCE=npm PROOF_LLM=1 node test/install-proof.mjs # npm plugin path (once published)

knobs: PROOF_REPO, CHROME_BIN, PROOF_PORT, PROOF_KEEP=1 — see the script header.

License

MIT.