Cline and Roo Code (a popular Cline fork) are open-source AI coding agents that live inside VS Code as an extension rather than a separate editor, currently around #25 in real-world usage (roughly 2.2% share combined). They offer agentic, multi-step task execution without a subscription fee — you bring your own AI model API key instead.
📌 Quick facts
Type: AI coding agent (VS Code extension)
Made by: Open-source community projects
License: Free / open-source (bring your own API key)
Platforms: Runs inside VS Code — Windows, macOS, Linux
Primary use case: Agentic multi-step coding tasks inside your existing editor
Key features
- Installs as a normal VS Code extension — no separate editor to switch to
- Agentic loop: reads files, proposes edits, runs terminal commands, and iterates based on the results
- Bring-your-own API key — works with Claude, GPT, Gemini, or local models
- Diff-based review of every proposed edit before it's applied to your files
- Roo Code (the Cline fork) adds extra modes — Architect, Ask, Code — and deeper customization
- No subscription fee — you only pay for your own model provider's API usage
Getting started
# 1. Open VS Code → Extensions
# 2. Search for "Cline" or "Roo Code" and install
# 3. Open the extension panel and paste in your model provider's API key
🎯 Best for: developers who already live in VS Code and want agentic AI coding help without switching editors or paying a monthly subscription, using whichever AI model they prefer.