Cline

Cline is an open-source, autonomous AI coding agent that runs inside VS Code and can read files, write code, execute terminal commands, and browse the web — all with explicit human oversight at each step. It’s one of the most feature-rich AI coding agents available, and being fully open-source means you can inspect exactly what it does and extend it to fit your workflow.

What makes Cline distinctive is its MCP integration and marketplace. Rather than being a closed system, Cline supports the full Model Context Protocol and ships with a built-in marketplace of community-contributed MCP servers. Install servers for GitHub, Slack, web browsing, database access, and hundreds of other integrations from within VS Code, and Cline can use them as tools when completing tasks.

The agent operates with explicit permission prompts: before reading a file, executing a command, or making an API call, Cline shows you exactly what it’s about to do and waits for approval. This keeps you in control of potentially destructive operations while still enabling Cline to operate autonomously on safe tasks once you trust its plan.

Cline works with any LLM that has an API: Claude, GPT-4o, Gemini, and local models via Ollama. You connect your own API keys, so usage costs go directly to the provider without markup. This makes Cline particularly cost-effective for heavy users who would otherwise hit subscription limits.

The extension is free and available in the VS Code marketplace. Community support is active and the codebase is actively maintained with frequent feature additions.