Cline

Cline is an open-source, agentic AI coding assistant that runs primarily as a VS Code extension (with JetBrains, Cursor, Windsurf, and a CLI/SDK also supported) and behaves less like an autocomplete and more like a junior engineer sitting inside your editor. Given a natural-language goal, it plans a sequence of steps, opens files, writes coordinated multi-file diffs, runs terminal commands, reads the output, and iterates until the task is done — always surfacing every action for human approval via a diff view, checkpoints, and one-click undo. Its signature Plan/Act workflow forces the agent to lay out an approach and get sign-off before touching code, which makes it noticeably safer on non-trivial refactors than pure act-first agents. Cline is model-agnostic by design: you bring your own key (Anthropic Claude, OpenAI GPT, Google Gemini, DeepSeek, Grok, Mistral, Cerebras) or point it at local runtimes like Ollama and LM Studio, and it also speaks the Model Context Protocol so you can bolt on tools, databases, browsers, Jira/Linear/Slack, or CI pipelines. Project-level .clinerules files let you encode coding standards, architectural conventions, and guardrails the agent must follow. Typical workflows include bootstrapping features across many files, migrating APIs, writing test suites, chasing down failing CI runs, wiring up new integrations, and doing exploratory refactors on unfamiliar codebases. It has grown into one of the most popular open-source coding agents on GitHub with 64k+ stars, 250+ contributors, 8M+ installations, and adoption inside teams at Samsung, Salesforce, Oracle, Amazon, and Microsoft.