Cline Review 2026: The Free VS Code Agent That Punches Above Its Weight

Cline is the open-source VS Code extension that turned “bring your own API key” into a legitimate alternative to commercial AI coding tools. With over 5 million installs and an active community, it has grown from a simple chat sidebar into a genuine agentic coding assistant with plan/act modes, terminal execution, browser automation, and MCP (Model Context Protocol) support. We have been using it for five months, and it has earned a permanent spot in our toolkit — with some important caveats.

The Short Version

Rating: 4.0/5. Cline is the most capable free AI coding extension for VS Code. The Plan/Act workflow gives you a structured approach to complex tasks that most commercial tools lack. MCP support opens up integrations that go far beyond code editing. The browser automation feature — where Cline can actually interact with your running application — is genuinely innovative. The downsides: API costs add up faster than you expect, the extension can be slow with large contexts, and the quality of output varies dramatically depending on which model you connect. If you are already paying for Claude or GPT-4 API access, Cline is a no-brainer addition to your VS Code setup. If you are not, the total cost of ownership may surprise you.

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What Is Cline?

Cline (formerly Claude Dev) is a free, open-source VS Code extension that connects to AI models through their APIs and provides an agentic coding experience directly inside your editor. Unlike GitHub Copilot, which focuses on inline completions, or Cursor, which is a standalone editor, Cline operates as a sidebar panel in VS Code that can read your files, write code, execute terminal commands, and even interact with web browsers.

The “agentic” part is key. Cline does not just answer questions or suggest code snippets. It plans tasks, executes them step by step, asks for your approval at each stage, and can iterate based on results. When Cline runs a command and sees an error, it reads the error output and tries to fix it. When it creates a frontend component, it can open the browser, look at the result, and adjust the CSS. This loop — plan, execute, observe, adjust — is what separates Cline from simpler chat-based tools.

The extension supports multiple LLM providers: Anthropic (Claude), OpenAI (GPT-4), Google (Gemini), AWS Bedrock, local models via Ollama, and any OpenAI-compatible API endpoint. You bring your own API key, and Cline handles the rest.

Key Features: What Actually Matters

Plan Mode and Act Mode

Cline’s two-mode workflow is its most distinctive feature. In Plan Mode, you describe what you want and Cline creates a detailed plan — listing the files it will create or modify, the approach it will take, and any potential issues it foresees. You review the plan, suggest changes, and approve it before any code is written.

In Act Mode, Cline executes the plan step by step, showing you each file change and terminal command before running it. You approve each step individually, or you can enable auto-approval for trusted operations.

We used this workflow to add a complete notifications system to a Next.js application. In Plan Mode, Cline outlined: create a notifications table migration, add a Prisma model, build a notifications service with CRUD operations, create API routes, build React components for a notification dropdown and a notifications page, and add real-time updates via server-sent events. The plan was thorough and identified a dependency we had not considered — we needed to update our Prisma schema to add a relation to the existing User model.

After approving the plan with one modification (we wanted WebSockets instead of SSE), Act Mode executed everything across 11 files. It ran the Prisma migration, generated the client, created all the files, ran our lint check, found two ESLint errors, and fixed them. The entire process took about eight minutes. The code was not perfect — the WebSocket connection handling needed cleanup and the notification dropdown had a z-index issue — but the structural foundation was solid and saved us at least three hours of boilerplate work.

Terminal Execution

Cline can run terminal commands directly from the VS Code integrated terminal. This sounds simple, but it changes the workflow significantly. When Cline writes code that depends on a new package, it installs the package. When it creates a migration, it runs the migration. When it writes a test, it runs the test and reads the output.

The approval flow is important here. By default, Cline asks permission before running any terminal command. You see the exact command and can modify or reject it. For safe commands like npm install or npx prisma generate, you can add them to an auto-approve list. For commands that modify data or affect infrastructure, you keep manual approval on.

We had one memorable session where Cline was debugging a failing integration test. It ran the test, read the error (a missing environment variable), checked our .env.example file, added the variable to .env.test, re-ran the test, found a different error (wrong database URL format), fixed the URL, re-ran, and the test passed. Four iterations, no manual intervention needed beyond approving the commands. That kind of autonomous debugging loop is genuinely impressive.

MCP (Model Context Protocol) Support

MCP support is what makes Cline more than a coding assistant. MCP is a protocol that lets AI tools connect to external services and data sources. Cline can use MCP servers to access databases, APIs, documentation sites, Figma designs, and more — all as context for its coding tasks.

We connected Cline to a PostgreSQL MCP server and asked it to “build an API endpoint that returns the top 10 customers by lifetime revenue.” Instead of guessing at our schema, Cline queried the database to inspect the table structure, identified the relevant tables and columns, and generated a query that was correct on the first attempt. Without MCP, we would have had to paste our schema into the chat manually.

The MCP ecosystem is still young, but it is growing. Servers exist for GitHub, Slack, Jira, Linear, Notion, PostgreSQL, and more. Each one extends what Cline can do. The setup requires some technical comfort — you are running local servers and configuring JSON files — but the payoff is significant.

Browser Automation

Cline can launch a browser, navigate to a URL (typically your local dev server), take screenshots, and use those screenshots to understand the visual state of your application. This creates a feedback loop for frontend development that no other coding assistant offers.

We asked Cline to “fix the layout issues on the settings page.” It opened Chrome, navigated to localhost:3000/settings, took a screenshot, identified that the sidebar was overlapping the main content on narrow viewports, edited the CSS, refreshed the page, took another screenshot, and confirmed the fix. We approved the final diff. The whole exchange took about two minutes.

The browser automation is not full Selenium-level scripting. It is visual — Cline looks at screenshots and reasons about what it sees. This works well for layout issues, visual bugs, and basic UI verification. It does not work well for testing complex interactions, animations, or anything that requires precise timing.

Pricing: Free Extension, Real API Costs

Cline is free. The extension itself costs nothing — it is open-source under the Apache 2.0 license. There is no subscription tier, no premium features, no usage cap from Cline itself.

Your costs come entirely from the API provider you choose. Here is our actual monthly spending breakdown during typical use:

• Claude 3.5 Sonnet via Anthropic API: $50-80/month with moderate daily use. Cline sends large contexts (file contents, terminal output, screenshots), so token usage is high.
• GPT-4o via OpenAI API: $30-50/month for similar usage. Slightly cheaper per token but we used Claude more for quality reasons.
• DeepSeek or local models: Under $10/month, but with noticeably lower quality for complex tasks.

Our typical all-in monthly cost was $60-90. That is more than a Cursor Pro subscription and more than GitHub Copilot. The irony of “free” tools is real. You are not paying for the tool; you are paying for the intelligence — and in Cline’s case, you are paying retail API rates without the bulk discounts that commercial tools negotiate.

Some strategies to manage costs: use Plan Mode first (cheaper, since it does not generate as many tokens), switch to cheaper models for routine tasks, use the auto-context feature sparingly (manually selecting files instead of letting Cline read everything), and keep an eye on your API dashboard.

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Pros and Cons

What We Love

• Plan/Act workflow is the best structured approach to agentic coding we have seen. It prevents the AI from going off the rails on complex tasks.
• MCP support makes Cline extensible in ways that closed-source tools cannot match. Connecting to databases, APIs, and design tools as context sources is powerful.
• Browser automation creates a visual feedback loop for frontend development that nothing else offers.
• Terminal execution with approval flows strikes the right balance between autonomy and control.
• Model flexibility lets you choose the best model for each task and avoid vendor lock-in.
• Open-source and transparent. You can read every line of code. The community is active and features land quickly.
• Works inside VS Code. No new editor to learn. Your extensions, themes, and keybindings stay exactly as they are.

What Frustrates Us

• API costs are opaque until you check your dashboard. Cline shows token counts, but translating that to dollars requires mental math. A cost-per-request display would help enormously.
• Large context handling is slow. When Cline includes multiple large files plus terminal output plus screenshots, the response time can stretch to 30+ seconds. With Claude, we occasionally hit rate limits during intensive sessions.
• No inline autocomplete. Like Aider, Cline is entirely chat/task driven. You do not get passive suggestions while typing. For that, you still need Copilot or Cursor’s Tab feature.
• Output quality depends entirely on the model. Cline with Claude 3.5 Sonnet is excellent. Cline with a budget local model is mediocre. The tool is only as smart as the LLM behind it.
• Extension stability has improved but is not perfect. We experienced occasional freezes during long sessions, particularly when browser automation was involved. Restarting the extension resolves it, but it is disruptive.
• Configuration complexity. Setting up MCP servers, managing API keys, configuring auto-approval rules — there is a lot of knob-turning to get Cline working optimally.

Cline vs. the Competition

Compared to Cursor, Cline offers MCP support and browser automation that Cursor lacks, but Cursor provides a dramatically better editing experience with Tab completions and Composer. If you want the best all-in-one coding experience, Cursor is still the pick. If you want agentic capabilities and extensibility inside VS Code, Cline offers things Cursor cannot. See our Cursor review for a detailed look at what Cursor does well.

Compared to GitHub Copilot, Cline is more capable for complex, multi-step tasks but less useful for everyday inline coding. Copilot’s completions are faster and more seamlessly integrated. Cline’s Plan/Act workflow is better for feature-level work. Many developers run both — Copilot for completions, Cline for agentic tasks. For a full breakdown, read our Cline vs Copilot comparison.

Compared to Aider, both are open-source and model-flexible, but they serve different niches. Aider has superior Git integration and works in the terminal. Cline has a richer UI, browser automation, and MCP support. Aider is better for developers who live in the terminal; Cline is better for developers who live in VS Code.

Compared to Claude Code, Cline offers a more visual, GUI-driven experience while Claude Code offers deeper reasoning and a more powerful terminal workflow. Claude Code is better for complex problem-solving; Cline is better for structured task execution with visual feedback. See our Claude Code vs Cline comparison for the full head-to-head, or read our Claude Code review for more on that tool. We also have a Windsurf vs Cline comparison if you are deciding between agentic editors.

Who Should Use Cline

Cline is the right choice if you:

• Use VS Code as your primary editor and want agentic AI without switching editors
• Already have API keys for Claude, GPT-4, or other models and want to use them directly
• Work on full-stack projects where browser automation and terminal execution add value
• Want an extensible tool that can connect to databases, APIs, and other services via MCP
• Prefer open-source tools you can audit and contribute to
• Do not mind managing your own API costs

Cline is probably not for you if you:

• Want predictable monthly costs with no usage surprises
• Need inline autocomplete while typing — Cline does not provide this
• Are looking for a simple, zero-configuration experience
• Prefer a standalone editor purpose-built for AI (that is Cursor)
• Work in an environment where sending code to external APIs is prohibited

The Bottom Line

Cline represents the best of what open-source AI tooling can be. The Plan/Act workflow is thoughtful and effective. MCP support makes it future-proof in a way that closed-source tools are not. Browser automation is a genuine innovation that we expect commercial tools to copy. And the fact that all of this is free — truly free, with no artificial limitations — is impressive.

The “free” label deserves an asterisk, though. Our $60-90/month API bills mean Cline is not cheap to use well. It is free as in freedom, not free as in beer. You are paying for the AI models directly, and you are paying retail rates. For some developers, that flexibility is worth the premium. For others, a flat subscription to Cursor or Copilot is a better deal.

We use Cline alongside Copilot: Copilot for inline completions, Cline for multi-step tasks and anything that benefits from terminal execution or browser feedback. That combination has been the most productive VS Code setup we have tested.

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