Chapter 1
Agent Harnesses
The desktop app, IDE, or platform that connects AI to your code. No terminal required.
What Is an Agent Harness?
An agent harness is the application where you talk to an AI coding agent. It gives the AI tools to read and edit files, search the web, run commands, and manage your project. It also controls what the AI is allowed to do and keeps your code private.
Think of it as the dashboard for AI-assisted development. The harness determines:
- What tools the AI can use (file editing, web search, terminal access)
- How you interact (desktop app, web browser, IDE, or terminal)
- Permission model (auto-approve, ask first, or deny per action)
- What models you can connect (75+ providers, local models, API keys)
OpenCode Desktop — Built for Normal Users
OpenCode Desktop is the agent harness we recommend for anyone who doesn’t want to work in a terminal. It’s a full desktop application for macOS, Windows, and Linux. Open source (Apache 2.0), built by Anomaly, with 160,000+ GitHub stars and 7.5M+ monthly developers.
160K+
GitHub Stars
900+
Contributors
7.5M+
Monthly Developers
75+
LLM Providers
Why Desktop?
Most guides push you toward the terminal. That’s unnecessary. OpenCode Desktop gives you the same AI coding power in a familiar windowed app:
- No terminal knowledge needed — open the app, pick a project folder, start chatting
- Visual file browser — see your project structure, click to open files
- Settings panels — connect providers, manage MCP servers, configure permissions through UI
- Plan Mode toggle — switch between planning and building with a button
- Session management — multiple conversations, shareable links, undo/redo
Installation — Download & Go
macOS (Apple Silicon)
DMG installer · M1/M2/M3/M4
macOS (Intel)
DMG installer · Intel Macs
Windows
NSIS installer · 64-bit
Linux
.deb / .rpm · 64-bit
macOS users can also install via Homebrew:
brew install --cask opencode-desktopSource: opencode.ai/download
First Launch — What Happens
After installing and opening the Desktop app:
- Pick a project folder — Open any folder on your computer. The AI reads your files.
- Connect a model — Go to Settings, pick a provider (OpenCode Go, DeepSeek, z.ai, Moonshot, etc.), sign in or paste your API key. Or start with free models.
- Start chatting — Type what you want to build. The AI reads your project, plans changes, and builds them.
That’s it. No config files, no environment variables, no terminal commands.
Key Features for Web Development
| Feature | Why It Matters |
|---|---|
| Plan Mode | AI proposes changes without executing — you review before anything gets built. Toggle it in the UI. |
| MCP Server Support | Connect to PageWeave, databases, and APIs. Manage MCP servers in the Settings panel. |
| Agent Skills | Load SKILL.md files that teach the AI your workflows. Skills Manager in Settings. |
| Multi-Session | Run multiple AI conversations in parallel on the same project. |
| Share Links | Share any conversation via URL for feedback or debugging. |
| LSP Integration | Real-time diagnostics, autocomplete, and go-to-definition for your programming language. |
| Undo / Redo | Revert AI changes with one click — preserve context and try again with better instructions. |
| Privacy-First | No code stored server-side. Works offline. Your files never leave your computer unless you choose a cloud model. |
| 75+ Model Providers | Connect any model: OpenCode Go ($10/mo), DeepSeek, z.ai, Moonshot, MiniMax, OpenAI, Anthropic, local models. |
Terminal also available: OpenCode works in terminal, web browser, and as a VS Code/Cursor extension. Desktop is the recommended entry point. Power users can use the terminal version (
brew install opencode) with the same features.How OpenCode Works with PageWeave
In OpenCode Desktop, go to Settings → MCP Servers and add the PageWeave MCP server. Once connected, the AI gains tools to create websites, write pages, manage themes, upload assets, configure domains, and more — all through the PageWeave platform.
You describe a website in plain English: “Build a dark-themed landing page with hero section, card grid, and scroll animations.” The AI creates it on PageWeave. Preview it instantly. No deployment, no servers, no build steps.
Alternatives Worth Knowing
IDE Extension
Microsoft’s AI pair programmer inside VS Code and JetBrains. Good for inline code completions. Less suited for autonomous multi-step web development — no MCP support, no plan mode, no agent skills.
Source: github.com/features/copilot
AI-First IDE
A VS Code fork rebuilt for AI. Strong at cross-file edits and codebase understanding. Better than Copilot for multi-step work. However, no MCP support means it can’t directly connect to PageWeave or external tools.
Source: cursor.com
Terminal (Python)
Python-based terminal agent with git-integrated editing. Strong for developers who prefer explicit git workflows. Terminal-only — no desktop GUI. Fewer platform integrations than OpenCode.
Source: aider.chat
Terminal (Anthropic)
Anthropic’s official agent. Tight Claude integration but limited to Anthropic models. Terminal-only. No MCP support. Closed source.
Source: docs.anthropic.com
Decision Framework
For building websites with AI, consider these factors when choosing a harness:
- Desktop App? Do you want a familiar windowed app, or are you comfortable in a terminal? OpenCode Desktop is the only open source option with a full GUI.
- MCP Support? Can it connect to PageWeave or other platforms? Only OpenCode supports MCP natively.
- Plan Mode? Can you preview changes before they’re made? Essential for building websites you care about.
- Model Choice? Can you use Chinese open-weight models (GLM-5.2, DeepSeek V4)? OpenCode supports 75+ providers including all Chinese open-weight options.
- Price? OpenCode Desktop is free. Models via OpenCode Go cost $10/mo. Direct API pricing is even cheaper.
Our recommendation: Download OpenCode Desktop → connect PageWeave MCP → subscribe to OpenCode Go ($10/mo) for models. Free app, cheap models, instant websites. No terminal needed.
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