Cline

What it is

Cline is an open source AI coding agent, released under Apache-2.0, that reads a repository, edits files across it, and runs terminal commands while watching their output. It ships as a VS Code extension, a JetBrains plugin, a standalone desktop app, a terminal CLI (npm i -g cline), and an SDK for embedding the same agent runtime in another product. The agent runs in Plan mode to work out a strategy first, then Act mode to execute it, with each file edit or command needing your approval unless auto-approve is switched on.

Nothing about the editor is forked. Cline bolts onto whatever you already use, which is the opposite approach from Cursor, which forked VS Code itself to build the agent in.

Who should use it

Developers who are comfortable holding their own API keys for Claude, GPT, Gemini, or a local model through Ollama or LM Studio, and who want to keep paying their model provider directly instead of a flat editor subscription. It also suits anyone who wants the agent outside an IDE entirely: the CLI runs headless in GitHub Actions or GitLab pipelines, and the SDK lets a team build their own tool on top of the same runtime. A developer who wants a single predictable invoice, or who doesn’t want to manage keys at all, is better served elsewhere.

What stands out

The pricing structure itself is a design choice, not an afterthought. Open source carries no subscription or seat fee anywhere, and the only dollar figure Cline’s own pricing page names is “custom” for Enterprise. Individual use is either bring-your-own-key, where you pay Anthropic, OpenAI, Google or another provider at their own rates, or Cline’s own inference credits, billed by usage and described on the pricing page as being sold “at cost.”

Plan and Act is a genuinely different interaction model from a single auto-editing agent. Plan mode forces a stated strategy before any file changes, and Act mode then executes with diffs, checkpoints and one-click undo on every step, so a reviewer always has a point to roll back to rather than trusting the agent not to have gone sideways three tool calls ago.

The reach past the editor is unusually wide for an open source project. A desktop app runs the agent without any editor at all, the CLI gives scriptable, JSON-output automation for CI, and the SDK (@cline/sdk) lets another company build its own branded tool on the same engine. Chat integrations for Slack, Discord, Telegram and Linear, plus multi-agent teams and cron-scheduled agents, round out a feature set built for running the agent unattended, not just inside a code editor.

The GitHub repository backs up the scale: roughly 70,000 stars and 7,700 forks at the time of writing, with Cline’s own site claiming over 11 million developers use it across its apps and extensions.

The verdict

Cline earns its place for one reason: it is a serious, actively developed agent that costs nothing beyond the tokens you use, works with any model you choose, and never locks you into a specific editor or vendor. For a developer who already treats API keys as a normal cost of doing business, that is a better deal than any flat subscription.

The risk is the flip side of what makes it cheap for a light user: a long agent session with a model that gets stuck in a loop runs the meter with no ceiling, because there is no included allowance standing between the agent and your card. Cursor and GitHub Copilot both cap usage inside a subscription tier you can budget against; Cline does not, by design. If an unpredictable bill from your own model provider would be a real problem, or you simply don’t want to manage API keys, pick a subscription product instead.