OpenCode VSCode Extension

Install for VSCode

A VSCode sidebar extension for OpenCode - the AI coding agent. Simple chat interface to interact with OpenCode directly from your sidebar.

Note: This is an independent community project and is not officially affiliated with or maintained by the OpenCode team.

Prerequisites

1. OpenCode CLI must be installed:

   curl -fsSL https://opencode.ai/install | bash

2. OpenCode must be configured with API credentials:

   opencode auth login

   Select your provider (OpenCode Zen, Anthropic, OpenAI, etc.) and add your API key.

Development Setup

Install Dependencies

pnpm install

Build the Extension

pnpm build

This builds both:

• Extension code → dist/extension.js
• Webview UI → out/main.js and out/main.css

Development Workflow

1. Start watch mode (in a terminal):

   pnpm watch

2. Launch Extension Development Host:

   • Press F5 in VSCode/Cursor
   • Or open Run and Debug panel (Cmd+Shift+D) and click "Run Extension"

3. Use the extension:

   • Look for the OpenCode icon in the Activity Bar (left side)
   • Click it to open the sidebar
   • Type a message and hit Send or press Enter

Making Changes

• Extension code (src/extension.ts, src/OpenCodeService.ts, src/OpenCodeViewProvider.ts):

  • Save your changes
  • Reload the Extension Development Host window: Cmd+R (Mac) or Ctrl+R (Windows/Linux)

• Webview UI (src/webview/App.tsx, src/webview/App.css, src/webview/hooks/):

  • Changes hot-reload automatically
  • Just save and see updates instantly

How It Works

Architecture

┌─────────────────────────────────────┐
│  SolidJS Webview (Chat UI)         │
│  - Input box                        │
│  - Message history                  │
│  - Thinking indicator               │
└──────────┬──────────────────────────┘
           │ postMessage
           ▼
┌─────────────────────────────────────┐
│  Extension Host (Node.js)           │
│  - OpenCodeService                  │
│    ├─ Manages OpenCode client      │
│    ├─ Creates sessions              │
│    └─ Sends prompts                 │
└──────────┬──────────────────────────┘
           │ @opencode-ai/sdk
           ▼
┌─────────────────────────────────────┐
│  OpenCode Server (Bun process)      │
│  - Spawned by extension backend     │
│  - Uses workspace opencode.json     │
│  - Handles AI interactions          │
└─────────────────────────────────────┘

Key Components

Extension Side (TypeScript/ESM):

• src/extension.ts: Entry point, initializes OpenCodeService
• src/OpenCodeService.ts: Manages OpenCode client/server, sessions, and prompts
• src/OpenCodeViewProvider.ts: Webview provider, handles message passing

Webview Side (SolidJS):

• src/webview/App.tsx: Chat UI with input, message history, thinking indicator
• src/webview/App.css: Styles using VSCode theme variables

Build System:

• vite.config.extension.ts: Bundles extension (ESM → CJS for VSCode)
• vite.config.ts: Bundles webview (SolidJS)

Configuration

The extension automatically uses:

1. Workspace opencode.json (if present in project root)
2. Global OpenCode config at ~/.config/opencode/opencode.json

Example workspace config:

{
  "model": "anthropic/claude-3-5-sonnet-20241022",
  "mcp": {
    // MCP server configurations
  }
}

Project Structure

opencode-gui/
├── src/
│   ├── extension.ts              # Extension entry point
│   ├── OpenCodeService.ts        # OpenCode client/server manager
│   ├── OpenCodeViewProvider.ts   # Webview provider
│   └── webview/                  # SolidJS UI
│       ├── App.tsx               # Chat component
│       ├── App.css               # Styles
│       ├── hooks/                # SolidJS hooks
│       ├── main.tsx              # SolidJS entry point
│       └── vscode.d.ts           # VSCode API types
├── media/
│   └── icon.svg                  # Activity bar icon
├── dist/                         # Compiled extension (Vite output)
├── out/                          # Compiled webview (Vite output)
├── vite.config.extension.ts      # Extension build config
├── vite.config.ts                # Webview build config
├── tsconfig.json                 # TypeScript config
└── package.json

Tech Stack

• Extension: TypeScript (ESM), VSCode Extension API, OpenCode SDK
• Webview: SolidJS, TypeScript
• Build: Vite for both extension and webview
• Styling: CSS with VSCode theme variables
• Server: Bun (spawned process running OpenCode server)

Features

✅ Simple chat interface ✅ Send prompts and get AI responses ✅ Thinking indicator during processing ✅ Message history (user and assistant) ✅ Workspace configuration support ✅ Full TypeScript type safety ✅ VSCode theme integration

Future Enhancements

• Real-time streaming responses
• File attachments from workspace
• Markdown rendering in responses
• Code syntax highlighting
• Multi-session support
• Session persistence
• Undo/redo functionality

Publishing

To publish a new version:

1. Bump the version in package.json
2. Set environment variable: export OVSX_PAT=your_open_vsx_token
3. Login to VS Code Marketplace: npx vsce login <publisher>
4. Run: pnpm publish

This publishes to both VS Code Marketplace and Open VSX Registry.

Note: You'll need:

• A VS Code Marketplace Personal Access Token (PAT) from Azure DevOps with "Marketplace (Manage)" scope
• An Open VSX token set as OVSX_PAT environment variable

Troubleshooting

"Failed to start OpenCode"

• Install OpenCode CLI: https://opencode.ai/install
• Make sure OpenCode CLI is installed and on PATH:
  • macOS/Linux: which opencode
  • Windows: where opencode
• Configure authentication: opencode auth login
• If you installed OpenCode recently, fully restart VS Code so the extension host gets the updated PATH

"No response received"

• Check API credentials are valid
• Verify workspace has internet connection
• Check VSCode Developer Console for errors (Help → Toggle Developer Tools)