Cline and Roo Code: Open-Source VS Code Agents
Cline and its fork Roo Code are open-source coding agents that live inside VS Code. You bring your own API key (BYOK), so nothing is hidden: every plan, prompt, file diff, and shell command is visible and human-approved step by step, any model can be plugged in — even a fully local one — and MCP servers extend its tools. They are the transparency counterweight to closed agent IDEs.
01.The Problem: Who Is Reading My Code?
Every tool so far has asked you to trust a pipeline you cannot see (Topics 269–274):
- Cursor indexes your repo on its servers.
- Devin runs your code in its cloud VMs.
- Replit hosts your whole app in its platform.
Fine, until the security team asks the blunt questions:
Exactly what leaves this machine? Where is my code stored? Which model saw it, under whose contract?
Closed products answer with a policy page. Some engineers want a different answer: read the source yourself.
So the question becomes
Is there an agentic coding tool that is open source, shows every single step, and never stands between me and the model?
That is the lane of Cline and Roo Code — VS Code extensions, not new IDEs, running the same plan-edit-run loop as the commercial agents, but with the hood left open.
Cline / Roo Code Architecture
Cline / Roo Code Architecture
Separate VS Code extensions running a transparent plan→act loop where every file diff and shell command is human-approved, any model can be plugged in, and MCP servers extend tooling.
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