Monster coding agent lives in your IDE - moving beyond a CLI bridge to a fully native IDE AI assistant.

Shipped to vscode marketplace and it's compatible IDEs, i.e., cursor, windsurf, antigravity, etc., marketplaces

• Native Chat Interface: Deeply integrated webview clean ui for smooth chat interactions inside VS Code (and/or its clone/fork IDEs).
• Embedded AI Engine: Run Coder's powerful AI logic directly within the extension process - no external CLI tool required.
• Project-Aware Context: Automatically understands your workspace structure and active files.
• Smart Tools:
  • read_file: Intelligently reads file contents with progressive loading for large files.
  • write_file, find_files, and more (Coming Soon).
• Live Diff Preview: Preview AI-suggested code changes with standard VS Code diff views.
• Diagnostics Integration: Uses LSP diagnostics to help fix errors in your code.

• Visual Studio Code version 1.104.0 or higher
• coder.config.json in your workspace root (for configuring AI providers).

1. Installation: Install the extension from the VS Code Marketplace or via .vsix.

2. Configuration: Ensure you have a coder.config.json in your project root (see setup examples below, can be any OpenAI compatible API or local/self-hosted API).

   lmstudio (localhost) example:

   {
     "coder": {
       "providers": [
         {
           "name": "lmstudio",
           "models": [
             "openai/gpt-oss-20b"
           ],
           "baseUrl": "http://localhost:1234/v1"
         }
       ]
     }
   }

   ollama (localhost) example:

   {
     "coder": {
       "providers": [
         {
           "name": "ollama",
           "models": [
             "gpt-oss:20b"
           ],
           "baseUrl": "http://localhost:11434/v1"
         }
       ]
     }
   }

   fetch from any api provider, see example below:

   {
     "coder": {
         "providers": [
           {
             "name": "openrouter",
             "baseUrl": "https://openrouter.ai/api/v1",
             "apiKey": "your-api-key",
             "models": ["anthropic/claude-4.5-sonnet"]
           }
         ]
     }
   }

3. Launch: Click the "Code" monster icon in the Activity Bar (left sidebar) to open the chat.

• Chat: Type naturally in the chat window. "Explain this file", "Fix this bug", etc.
• Context: The assistant automatically knows about your open files.

This extension has migrated from a thin client (CLI bridge) to a thick client architecture:

• Frontend: React + Vite (Webview).
• Backend: Node.js Extension Host (running ai-sdk-client).
• Communication: VS Code Message Passing API.

npm install

# Build both Webview and Extension
npm run build

# Watch mode (rebuilds on change)

# Terminal 1:
npm run watch:webview

# Terminal 2:
npm run watch

Contributions are welcome!

MIT