Cline

Cline is an open-source autonomous coding agent that lives inside the tools developers already use rather than asking them to switch editors. Released originally as Claude Dev and distributed under the Apache 2.0 license, it runs as a sidebar in VS Code, as a plugin for JetBrains IDEs, as a terminal CLI, and as an embeddable runtime, all powered by the same engine. Unlike an autocomplete tool that suggests the next line, Cline is a true agent: it reads a codebase, plans an approach, creates and edits files, runs terminal commands, and can even drive a real browser to test the result, iterating through an implement-test-fix loop until the task is done.

Control and transparency are central to how it works. Cline splits work into Plan and Act modes: in Plan mode it explores the code and lays out a strategy, asking clarifying questions, and in Act mode it carries that plan out. By default every file edit and terminal command is presented for your approval before it runs, so you see exactly what will change, though you can switch on auto-approve to let it run unattended. Coordinated multi-file edits come with diffs, checkpoints, and one-click undo at each step.

Because it is model-agnostic and bring-your-own-key, Cline works with every major provider, including Anthropic, OpenAI, and Google, as well as local models through Ollama, so teams can keep sensitive code on their own infrastructure, including air-gapped deployments. There is no Cline subscription; you pay only for the inference you use. A .clinerules file in a repository teaches the agent a project's standards and conventions, and first-class Model Context Protocol support lets it reach databases, API docs, issue trackers, and monitoring tools.

Beyond a single editor session, Cline can run headlessly in CI pipelines and on cron schedules, coordinate multiple agents where a lead delegates to specialists, and be driven from chat tools like Slack and Linear. It has become one of the most widely used open-source coding agents, favored by developers who want agentic capability without giving up their existing setup, their choice of model, or control over their data.