Cline

Definition

Cline is an open-source autonomous coding agent distributed as a VS Code extension. It lets a large language model create and edit files, execute terminal commands, and browse the web inside the editor, with a human-in-the-loop approval flow for each action, supporting multiple model providers including Anthropic, OpenAI, and local models.

Overview

Cline (formerly known as Claude Dev) started as a community project demonstrating that an editor extension could give an LLM near-full control of a developer's workspace: file read/write, terminal execution, and even a headless browser for testing web apps. It has since grown into a widely used open-source agent that is model-agnostic, letting users plug in Claude, GPT, Gemini, or self-hosted models via OpenAI-compatible or provider-specific APIs. Its core interaction loop is transparent by design: for every proposed file edit or command, Cline shows a diff or command preview and asks for approval (or runs automatically if the user has enabled auto-approve for that action type). This makes it popular with developers who want agentic capability but also want visibility and control over what gets executed on their machine. Cline supports the Model Context Protocol (MCP), so it can be extended with external tools — databases, issue trackers, custom APIs — the same way Claude Code and other MCP-compatible agents can. It also maintains a persistent task context and can checkpoint/rollback file states, letting users experiment with agent-driven changes without losing the ability to revert. Because it's open source and provider-neutral, Cline is often used as a reference implementation or comparison point when evaluating agentic coding tools, and its extension architecture has inspired several forks and derivative projects in the VS Code marketplace.

Key Features

• VS Code extension with a chat-driven agent interface
• Model-agnostic: works with Claude, GPT, Gemini, and local/self-hosted LLMs
• Shows diffs and command previews before applying changes
• Can execute terminal commands and read their output
• Built-in headless browser for testing and debugging web UIs
• Model Context Protocol (MCP) support for custom tool integrations
• Checkpoints workspace state so changes can be rolled back
• Fully open source with an active community and plugin ecosystem

Use Cases

Alternatives

History

Cline (originally named "Claude Dev") is an open-source autonomous coding agent that runs as a Visual Studio Code extension. It was created by Saoud Rizwan and first released in 2024 under the Apache 2.0 license. Cline reads and edits files in the active workspace and can run terminal commands — pausing for explicit user approval at each step — to work through multi-step development tasks. It is bring-your-own-key by default, letting developers connect their own Anthropic, OpenAI, OpenRouter, AWS Bedrock, Google, or Azure credentials so the extension itself stays free. Cline became one of the most popular open-source AI coding agents, later expanding to a CLI and additional editor integrations.

Frequently Asked Questions

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