Cline

Cline, originally known as Claude Dev, has grown into one of the most popular open-source AI coding agents for VS Code. Unlike code completion tools that suggest the next few lines, Cline operates as a full agentic assistant that can read your project files, plan implementations, create and edit multiple files, run terminal commands, and even browse documentation online -- all within your existing VS Code workspace. The key advantage over tools like Cursor is that you stay in VS Code rather than switching to a fork, keeping all your extensions, keybindings, and configurations intact.

The bring-your-own-key model is both a strength and a consideration. On one hand, it means Cline itself is completely free with no subscription tiers or feature gates. On the other hand, API costs from providers like Anthropic or OpenAI can add up quickly during complex agentic tasks that require many back-and-forth iterations. Cline does an excellent job of surfacing cost information per task, so you can see exactly how much each operation costs and make informed decisions about when to let it run autonomously versus stepping in manually. The support for multiple providers also means you can switch between models depending on the task -- using a cheaper model for simple edits and a more capable one for complex refactoring.

Where Cline shows its open-source roots is in the polish department. The approval workflow, where you confirm each file edit and command execution, is thorough but can feel tedious compared to more streamlined commercial tools. The quality of output varies significantly depending on which AI model you use behind it, and the tool occasionally makes more aggressive changes than necessary when a targeted edit would suffice. Still, for developers who want agentic coding capabilities without leaving VS Code, without paying a subscription, and with full transparency into costs and changes, Cline is the strongest option available. The active community and rapid development pace suggest it will continue closing the gap with commercial alternatives.