Free, open-source VS Code AI agent extension offering autonomous coding with transparent human-in-the-loop control and 30+ LLM provider support.
Why it matters now: Free, open-source AI agent with transparent human-in-the-loop control and multi-provider LLM support.
Cline is an open-source autonomous coding agent available as a VS Code extension (and now on JetBrains, Cursor, Windsurf, Zed, Neovim, and a preview CLI). Originally launched as ‘Claude Dev’, Cline has grown into one of the most adopted AI coding agents with 60k+ GitHub stars and 5M+ installs. Its defining philosophy is human-in-the-loop transparency: Cline proposes each file edit and terminal command, waits for your approval, and keeps you in full control of what gets executed.
The architecture supports 30+ LLM providers, meaning you bring your own API keys or optionally use Cline’s pay-as-you-go inference credits. A May 2026 SDK release transformed Cline from a single extension into an open-source agent runtime, enabling third-party integrations and a CLI for macOS/Linux.
Cline’s strongest advantage is cost: completely free as open-source, with optional managed inference. The main trade-off is the human-in-the-loop model — every action requires approval — trading autonomy for control.
VS Code, Node.js runtime, internet connection; also available on JetBrains, Cursor, Windsurf, Zed, Neovim, and CLI (macOS/Linux preview).