Cline

Cline is a popular open-source VS Code agent that plans, edits, and runs commands with human-in-the-loop approval at every step.

Overview

Cline is an autonomous coding agent that runs inside Visual Studio Code, handling tasks from small fixes to feature-sized work. It builds a plan, edits files with reviewable diffs, and can execute terminal commands, always pausing for your approval before anything touches your system. The extension is model-agnostic, connecting to Anthropic, OpenAI, Google, and local providers through your own API keys. Checkpoints let you snapshot and restore a workspace state at any point in a task.

Cline’s appeal lies in the balance between autonomy and oversight. The agent can work through a long task, yet nothing is written or executed without a checkpoint the developer can inspect, which addresses one of the main trust barriers to AI coding tools. Community-contributed rules and MCP servers extend the agent into databases, browsers, and internal tooling.

Because the project is open source and model-agnostic, teams avoid lock-in and can route tasks to cheaper or local models when appropriate, reserving premium models for complex work.

Key Features

• Plan and Act modes that separate research and design from actual code changes
• Human-in-the-loop approval for every file edit and terminal command
• MCP client support to plug in databases, browsers, and custom tool servers
• Checkpoints and rewind so experimental edits can be reverted instantly
• Browser automation for testing the UI changes it makes
• Cline Marketplace for sharing rules, MCP servers, and workflow templates

Pricing

Cline is free and open source as a VS Code extension. You bring your own model API key and pay that provider directly; optional hosted plans and team features are available for organizations that want managed billing.

Who Is It For

VS Code users who want agentic automation without surrendering control of their machine. It works well for developers who like reviewing diffs and terminal commands before they run.

FAQ

Is Cline free to use?

Yes, the extension is free and open source. Model usage is billed by whichever provider you connect.

Does Cline offer an API?

Cline is an editor extension rather than a hosted API, but it exposes an MCP server so other agents can call its tools, and it connects to any supported model API.

How does Cline compare to alternatives?

Against GitHub Copilot, Cline is more autonomous; against closed agents such as Cursor Composer, it is open source and lets you choose any model and approve every action.