Cline

What is Cline?

Cline is an open-source extension for Visual Studio Code that functions as an AI coding agent. According to the project’s GitHub repository and documentation, it is the most widely adopted tool in its category, with over 5 million installs and more than 65,000 stars. The extension works on a bring-your-own-model principle: instead of bundling a proprietary AI, it lets users connect their own language model (via an API key or local inference). No special markup or formatting is required to prompt the agent — it operates directly on the code and terminal. The tool’s source code is publicly available at github.com/cline/cline, and its primary website is cline.bot.

Who is Cline for?

Cline is designed for developers who already use VS Code and want an AI assistant that gives them full control over the underlying model. Because users provide their own model and API key, the extension appeals to teams and individuals concerned about data privacy, vendor lock-in, or variable usage costs. It also suits developers who need to switch between different models (local, cloud, or enterprise-hosted) without changing their editor workflow. The project’s strong open-source community and GitHub activity suggest that contributors and early adopters are comfortable customising the tool, but the basic install-and-connect experience targets a broader audience — any VS Code user willing to supply their own AI backend.

How much does Cline cost?

The extension itself is free. The pricing page lists a starting cost of $0 per month, and the entire codebase is open source. Users do, however, pay for the AI model they choose to connect — these costs vary by provider (e.g., OpenAI, Anthropic, local models) and are entirely separate from Cline. There is no premium tier or subscription required for the extension’s features. The documentation notes that users must supply their own API key, meaning the ongoing cost is driven by the model’s token pricing, not by Cline itself.