Cline: the open-source VS Code coding agent that splits Plan and Act
In one sentence Cline (formerly Claude Dev) cements the Plan/Act mode pattern in VS Code: model plans with the dev first, then acts. Open source, model-agnostic, 1M+ downloads. Becomes Cursor's main open competitor.
Cline is an open-source VS Code extension that turns the editor into a coding agent. Its hallmark vs Cursor or Copilot is the strict split between "Plan Mode" and "Act Mode": first the model discusses the plan with you, then it executes.
This pattern matters because it stops the agent from rushing to modify files based on a wrong idea of what you want. In Plan Mode the model can only read and reason; in Act Mode it can modify. You approve the switch.
By September 2025 it passes 1 million downloads and becomes the reference "open VS Code agent" for those who don't want to leave the classic editor but want agentic capabilities. It supports Claude, GPT, Gemini, local models via Ollama/LM Studio, and unlike Cursor doesn't require a proprietary backend.
Companies
Cline
Tools
Cline, Plan Mode, Act Mode
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