opencode Attach (Remote Edition) — VS Code Extension

A VS Code extension that attaches to an already-running opencode server and lets you keep working with your AI coding session from anywhere, via VS Code Remote Tunnel + a remote-browser control UI.

Unlike the upstream opencode extension, this fork never auto-spawns a server — you start opencode yourself (locally, in a Docker container, on a remote host via SSH, etc.) and tell the extension which port it's listening on.

Why

When opencode runs an AI coding task, it often pauses and waits for you to react:

• Waiting for your input (it asked a question)
• Waiting for permission (a shell command / file write needs approval)
• Waiting for operation confirmation (a destructive or notable action)
• Task complete (and you didn't notice because you walked away)
• Build failed
• Test failed
• Agent error

Today, the only way to react is to be at your desk. This extension closes that loop:

1. Tunnel. Uses VS Code Remote Tunnel to give your opencode session a stable public URL — no manual port forwarding, no auth to wire up.
2. Watch. Observes the running opencode session for the seven event types above.
3. Surface. Pushes them to a remote control UI you can open in any browser.
4. Respond. Lets you approve a permission, send input, view logs, etc. — from anywhere with a browser.

Prerequisites

• opencode CLI installed (or any opencode server binary reachable from your machine).
• An opencode server already running, listening on a known port (e.g. opencode serve --port 12345).
• VS Code Remote Tunnel enabled on this machine (sign in with GitHub / Microsoft, then turn the tunnel on). This extension reuses VS Code's tunnel — it does not start its own.
• A modern browser on any remote device (phone, tablet, or desktop — iOS Safari 16+, Android Chrome 110+, or any recent desktop browser).

Quick start

1. Start an opencode server in a terminal:

   opencode serve --port 12345
   

2. In VS Code, press Ctrl+Esc / Cmd+Esc. When prompted, enter the port (12345).
3. A terminal named opencode opens in the side panel with opencode attach http://localhost:12345 pre-filled. Press Enter to attach.
4. Make sure VS Code Remote Tunnel is running. The tunnel URL is shown in the VS Code status bar (look for Remote: <hostname>.devtunnels.ms or vscode.dev/tunnel/<...>). Click the status bar item, or run the Show Tunnel URL command from this extension to copy it.
5. Open the tunnel URL in a browser on any remote device. The remote control UI loads automatically.
6. Walk away. When opencode needs you, you get a notification and can respond without going back to the machine.

Features

Remote control UI

• Works through VS Code Remote Tunnel — no extra auth or open ports.
• Remotely synchronize local OpenCode sessions via the browser.

Event detection

The extension recognizes and surfaces the following opencode events to the remote UI:

Local UX (still works without the tunnel)

The original attach helpers remain, so the extension is useful even when you're at the machine (not remote):

Note: These keybindings conflict with the upstream opencode extension if both are installed. Resolve via Ctrl+K Ctrl+S → search opencode-attach → rebind.

Architecture

┌──────────────────────────┐         ┌──────────────────────────┐
│         Browser          │◀─HTTP─▶│  VS Code Remote Tunnel   │
│   (remote control UI)    │   (TLS) │  (auth: GitHub / MS)     │
└──────────────────────────┘         └────────────┬─────────────┘
                                                  │ (authenticated proxy)
                                                  ▼
                                        ┌──────────────────────────┐
                                        │  This VS Code Extension  │
                                        │  - localhost web server  │
                                        │  - SSE stream to browser │
                                        │  - watches opencode      │
                                        └────────────┬─────────────┘
                                                     │
                                          attaches to │ opencode attach
                                                     ▼
                                        ┌──────────────────────────┐
                                        │  opencode server         │
                                        │  (user-started, :12345)  │
                                        └──────────────────────────┘

Key design choices:

• Tunnel reuse, not DIY. VS Code's Remote Tunnel already handles auth, TLS, and connectivity. The extension binds to localhost only; VS Code proxies to it.
• Attach-only. No opencode spawn, no random-port server. The user owns the server lifecycle. (See docs/superpowers/specs/2026-08-31-opencode-vscode-attach-mode-design.md.)
• The extension is a thin adapter. It owns the tunnel endpoint, the web UI, and the event detector — it does not implement opencode itself.

Security

• The control UI binds to 127.0.0.1 only. It is reachable remotely exclusively through VS Code Remote Tunnel, which is authenticated with your GitHub / Microsoft account.
• The extension does not open any additional public ports and does not bypass VS Code's tunnel authentication.
• The extension does not store or transmit opencode credentials. It only attaches to the server the user started.
• Treat the tunnel URL like a private link — anyone with it and your tunnel account can reach your dev machine.

Coexistence with the upstream extension

This extension is published as yveguo.opencode-attach-vscode and registers all commands under the opencode-attach.* prefix. It does not touch the upstream sst-dev.opencode extension or its opencode.* commands. Both can be installed side by side.

Development

1. code . in this directory.
2. npm install (or bun install).
3. Press F5 to start debugging — this launches a new VS Code window with the extension loaded.

Testing the remote UI during dev

You can iterate on the remote UI without leaving your machine:

• The extension serves the UI on http://localhost:<port> (shown in the VS Code Output panel under this extension's name).
• Open that URL in a desktop browser, with DevTools device emulation set to a mobile viewport, to preview the UI.
• To test the full remote flow, enable VS Code Remote Tunnel on the debug session and open the tunnel URL from a separate device.

Making changes

tsc and esbuild watchers run automatically during debugging. Changes are rebuilt in the background.

To reload after changes:

1. In the debug VS Code window, press Ctrl+Shift+P / Cmd+Shift+P.
2. Search for Developer: Reload Window.
3. Reload to see your changes without restarting the debug session.

Packaging a .vsix

The repository's vscode:prepublish script assumes bun. To package without bun:

npx tsc --noEmit
npx eslint src
node esbuild.js --production
# temporarily swap "vscode:prepublish": "bun run package" to "node esbuild.js --production" in package.json
npx vsce package
# restore package.json

Support

This is a fork of anomalyco/opencode. Report issues at the upstream repo.