Cline
Open-source VS Code extension that gives AI models agentic capabilities to create files, run commands, and manage your codebase.
Best for: Developers who want an open-source agentic coding assistant in VS Code
What Is Cline?
Cline (formerly Claude Dev) is a free, open-source VS Code extension that turns any AI model into an agentic coding assistant. "Agentic" means the AI doesn't just suggest code — it can actually create files, edit existing code, run terminal commands, browse websites, and iterate on its work. You describe a task, and Cline executes it step by step, asking for your approval at each stage.
Think of Cline as bringing Cursor's AI capabilities into standard VS Code — but with the added benefit of being open-source and working with any AI provider you choose (Anthropic, OpenAI, Google, local models, etc.).
Who Is It Best For?
Cline is ideal for developers who want powerful agentic AI inside VS Code without switching to a different editor. It's particularly suited for:
- VS Code users who want Cursor-like AI features without leaving VS Code
- Developers who want to choose their own AI model and provider
- Open-source advocates who prefer transparent, community-built tools
- Developers who need agentic capabilities (file creation, terminal commands) beyond simple autocomplete
- Teams that want to standardize on an AI tool without vendor lock-in
If you just need basic autocomplete, Cline might be overkill — GitHub Copilot or Continue would be simpler. Cline's strength is in multi-step, agentic tasks where the AI needs to do more than suggest code.
Setup Walkthrough
Getting started takes about 5-10 minutes:
Step 1: Install the Extension
- Open VS Code
- Go to the Extensions panel (
Cmd+Shift+Xon Mac,Ctrl+Shift+Xon Windows) - Search for "Cline"
- Click Install on the official Cline extension
Step 2: Configure Your API Key
Cline needs an API key from your chosen AI provider:
- Click the Cline icon in the VS Code sidebar (it appears after installation)
- Click the settings gear icon
- Choose your provider and enter your API key
Popular options:
- Anthropic (Claude): Get a key at console.anthropic.com
- OpenAI (GPT-4): Get a key at platform.openai.com
- OpenRouter: Access multiple models with one key at openrouter.ai
- Ollama (local): Run models locally for free — no API key needed
Step 3: Start Using Cline
- Open the Cline panel from the sidebar
- Type a task: "Create a new React component for a user profile card"
- Cline will plan the task, then execute it step by step
- You approve each action — Cline won't modify files or run commands without your permission
Real Usage: Cline in Action
Here's what using Cline actually looks like in practice:
Scenario: You want to add authentication to your Express.js API.
- Open the Cline panel
- Type: "Add JWT authentication to the Express API. Include signup, login, and a middleware to protect routes. Use bcrypt for password hashing."
Cline will then proceed step by step:
Step 1: "I'll install the required packages." → Shows you the npm install command → You approve → It runs.
Step 2: "I'll create an auth middleware." → Shows the file it wants to create → You approve → It creates middleware/auth.js.
Step 3: "I'll add signup and login routes." → Shows the code changes → You approve → It modifies routes/auth.js.
Step 4: "I'll update the main app file to use the auth routes." → Shows the diff → You approve → Done.
The approval step is key. Unlike some agentic tools that run autonomously, Cline asks before every action. This makes it safer but slightly slower. You can adjust the auto-approve settings if you trust Cline to handle certain types of actions (like reading files) without asking.
Browser integration is a unique feature — Cline can open a browser, navigate to URLs, take screenshots, and interact with web pages. This is useful for testing and debugging visual issues.
Honest Pros & Cons
| Pros | Cons |
|---|---|
| Free and open source | Requires your own API key (costs vary) |
| Works with 20+ AI providers | Setup more involved than commercial tools |
| Agentic: creates files, runs commands, browses web | Quality depends heavily on chosen model |
| Stays inside VS Code — no editor switching | Can be token-hungry (expensive with premium models) |
| Step-by-step approval keeps you in control | Approval prompts can feel tedious for large tasks |
| Active community with frequent updates | UI can feel cluttered in the sidebar panel |
| Full transparency — read the source code | No inline autocomplete (it's a chat/agent tool) |
Cost Analysis
Cline itself is free. You pay for the AI model you use:
| Provider / Model | Typical Cost | Best For |
|---|---|---|
| Claude 3.5 Sonnet | ~$5-15/day active use | Best coding quality |
| GPT-4o | ~$3-8/day active use | Good balance |
| DeepSeek Chat | ~$0.10-0.50/day | Budget-friendly |
| Ollama (local) | $0 | Free, requires good GPU |
| OpenRouter | Varies by model | Access to many models, one API key |
What you actually need: For the best results, use Claude 3.5 Sonnet or a newer Claude model. It's the model Cline was originally built around (it was called "Claude Dev" originally). If budget is a concern, DeepSeek is remarkably capable for a fraction of the price.
Compared to Cursor ($20/mo): Your Cline costs depend on usage. Light use costs well under $20/month. Heavy agentic use (where Cline reads many files and makes many edits) can exceed $30-40/month with premium models. The trade-off: Cline gives you full model flexibility and works in standard VS Code.
Cline vs. Other Tools
Cline vs. Cursor
Both offer agentic AI coding, but:
- Cursor is a standalone editor with AI built in. More polished, includes autocomplete.
- Cline is a VS Code extension. More flexible, works with any model, but less integrated.
Choose Cline if: You want to stay in VS Code and choose your own AI model. Choose Cursor if: You want the most polished, all-in-one AI coding experience.
Cline vs. GitHub Copilot
Different categories:
- Copilot excels at inline autocomplete and code suggestions.
- Cline excels at multi-step agentic tasks (creating files, running commands).
Best approach: Use both together. Copilot for inline autocomplete, Cline for complex tasks.
Cline vs. Aider
Both are open-source and model-flexible:
- Aider runs in the terminal with excellent git integration.
- Cline runs in VS Code with a visual interface and browser integration.
Choose based on your workflow — terminal-first (Aider) vs. VS Code-first (Cline).
Tips for Better Results
- Choose the right model: Claude 3.5 Sonnet consistently produces the best results with Cline
- Be specific about the task: "Add user authentication with JWT and bcrypt to the Express API in src/routes/" beats "add auth"
- Add context files: Drag files into the Cline panel or mention them so it understands your codebase
- Use auto-approve wisely: Enable auto-approve for read operations to speed things up, but keep write approval on
- Check the cost tracker: Cline shows token usage per conversation — keep an eye on it for expensive models
Our Verdict
Cline is the best open-source agentic AI extension for VS Code. It brings Cursor-level AI capabilities to standard VS Code while giving you complete freedom to choose your AI provider. The step-by-step approval workflow keeps you in control, and the active open-source community means the tool improves rapidly.
The main trade-off is cost management. Since you bring your own API key, costs can sneak up during complex agentic tasks where the AI reads many files and makes many iterations. Monitor your usage, especially with premium models.
Rating: 4.0/5 — An excellent choice for VS Code users who want agentic AI without switching editors. We'd rate it higher once the token efficiency improves and the UI becomes less cluttered. But for the price of free (plus your API costs), it's hard to beat.