Cline Desktop is an open-source desktop application that lets you run AI agents without being locked into a specific model or provider. It grew out of Cline, which started as a VS Code extension now used by 11 million developers. The desktop app gives you access to 300+ models through various providers, or you can run open-weight models locally and bring your own API keys to connect to 50+ different services. What sets it apart is the underlying "harness" — the framework that determines how agents use tools, manage context, and handle errors. Cline rebuilt this foundation from scratch, rewriting prompts, simplifying the agent loop, and improving how models discover and call tools. The desktop workspace solves a real problem: as you delegate more work to agents, tracking multiple parallel sessions becomes messy in a code editor or terminal. Cline Desktop lets you run several agents simultaneously — one writing code, another researching in a browser, a third handling scheduled tasks. You can import conversations from Claude Code, Codex, or other agents and continue them with cheaper open-weight models, which matters if you've burned through subscription quotas. The app includes scheduling for cron job automations (morning PR reviews, nightly repo checks, weekly documentation updates), web search to pull in outside context, and voice input so you can talk through problems instead of typing everything out. The extensibility comes through a Marketplace where you can find and install plugins, MCP servers, and custom skills tailored to your workflow. The Mac version is fully open source, matching the extension and CLI, so all your Cline sessions stay connected — start something in the terminal, pick it up in the desktop app. The application is in early beta for Mac and Windows. The benchmarks show open-weight models performing reasonably well on Cline's Terminal-Bench 2.0, though those scores reflect the harness improvements rather than Desktop-specific testing.