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Posted on May 28 • Originally published at toolfreebie.com

Cline: Free Open-Source AI Coding Agent for VS Code (Cursor Alternative)

#ai #automation

What Is Cline?

Cline is a free, open-source AI coding agent that lives inside VS Code. Originally released as “Claude Dev” in 2024 and renamed to Cline in late 2024, the project has grown into one of the most popular autonomous coding assistants on the OpenVSX and VS Code marketplaces — over a million installs as of 2026, and a GitHub repo that consistently sits in the top of the trending charts (cline/cline, Apache 2.0).

Where editors like GitHub Copilot give you single-line completions and chat boxes, Cline does the whole task: it reads your repo, plans the change, edits multiple files, runs the terminal, opens a browser to verify, and waits for your approval at every irreversible step. It’s the same shape of agent you get from Cursor or Windsurf, except it costs nothing to install, runs against any model you point it at, and the extension itself is open-source code you can read line-by-line.

The catch — and the reason it pairs so well with the free AI APIs covered on this blog — is that Cline is BYOK (bring your own key). The extension is free, but the model calls go through whatever provider you configure. With a free Gemini, OpenRouter, Together AI, or Ollama backend, you can run Cline at zero marginal cost.

Cline vs Cursor vs GitHub Copilot

The three tools occupy overlapping but distinct positions. A side-by-side:

Feature	Cline	Cursor	GitHub Copilot
Price	Free (BYOK)	$20/mo Pro	$10/mo Individual
Editor	VS Code extension	Forked VS Code (separate app)	VS Code, JetBrains, others
Open source	Yes (Apache 2.0)	No	No
Choose your model	Anthropic, OpenAI, Gemini, DeepSeek, Groq, Together, Ollama, LM Studio, Bedrock, OpenRouter, LiteLLM	Cursor-managed (mostly Claude/GPT)	Mostly OpenAI, some Claude
Free model option	Yes — pair with any free API	Limited free tier	No
Autonomous multi-file edits	Yes (Act mode)	Yes (Composer / Agent)	Yes (Copilot Workspace, beta)
Terminal execution	Yes (with approval)	Yes	Limited
Browser automation	Yes (built-in)	Limited	No
MCP server support	Yes (native)	Yes	Limited
Plan-then-execute mode	Yes (Plan / Act toggle)	Partial	No
Token cost tracker per task	Yes (live, per request)	No (subscription)	No (subscription)

The headline trade-off: Cursor and Copilot give you a managed experience and predictable monthly bill. Cline gives you full transparency over the model, the prompts, and the per-token cost — at the price of wiring up your own API key. For developers who already keep Gemini, OpenRouter, or DeepSeek keys around for other projects, that wiring is a five-minute job.

Key Features That Matter

1. Plan and Act Modes

Cline’s marquee feature in 2026 is the explicit Plan/Act toggle in the input bar. In Plan mode, the model can only read files, search the workspace, and write you a step-by-step proposal — it cannot modify code or run commands. In Act mode, it executes that plan, asking for approval before each tool use it considers irreversible (file writes, terminal commands, browser actions).

This separation maps directly to how senior engineers actually work: think first, code second. It also dramatically reduces wasted tokens — a small reasoning model in Plan mode can often produce a workable plan that a cheaper executor model then fills in.

2. Bring-Your-Own-Model

The provider dropdown in Cline’s settings is the longest in the category. You can route the same conversation through any of: Anthropic (Claude 3.7/4 Sonnet, Opus), OpenAI (GPT-4o, GPT-4.1, o-series), Google Gemini, DeepSeek, Groq, Together AI, Mistral, OpenRouter, AWS Bedrock, GCP Vertex AI, Azure OpenAI, OpenAI-compatible local servers (Ollama, LM Studio, llama.cpp, vLLM), and LiteLLM proxies.

This matters for two reasons. First, you can pick the cost/quality point that matches the task — a tiny local model for boilerplate, a frontier model for the hard refactor. Second, it future-proofs your workflow: when a new state-of-the-art model lands, you point Cline at it the same day, no waiting for a vendor to integrate it.

3. Native MCP Support

Cline was one of the earliest agents to ship native support for the Model Context Protocol. Any MCP server — file system, GitHub, Postgres, Playwright, Slack, or your own — plugs into Cline’s tool list with no extra wiring. The MCP marketplace inside Cline lists hundreds of community servers you can install in two clicks.

Practically, this means Cline can do things outside the editor without you teaching it custom tools: query your production-replica Postgres, file a GitHub issue from a stack trace, or drive a Playwright browser to reproduce a bug a user filed.

4. Browser Automation Built In

Cline ships with a built-in headless browser tool. The agent can open a URL, screenshot the page, click on elements, type into fields, and read back the rendered DOM. The killer use case: “make this UI change and verify it visually” — Cline edits the React component, runs the dev server, opens the page, screenshots before/after, and only marks the task complete once the visual confirms the change.

5. Live Cost Visibility

Every task in Cline shows a running token counter and dollar estimate based on the current provider’s pricing. You can watch a multi-step refactor consume tokens in real time, and you can hit Stop the moment it stops being economical. No other agent in this category surfaces cost this directly.

How to Install Cline

Installation takes about thirty seconds:

Open VS Code (or VS Codium, Cursor, Windsurf — Cline runs in any VS Code-compatible editor)
Open the Extensions panel (Ctrl+Shift+X or Cmd+Shift+X)
Search for Cline (publisher: saoudrizwan)
Click Install
Click the new Cline icon in the activity bar
On first launch, Cline asks you to pick a provider and paste an API key

That’s it. Cline now sits in the side panel with an input box and a Plan/Act toggle. The extension itself never makes a network call until you give it a model and start a task.

Connecting Cline to Free APIs

The provider you pick determines whether Cline is genuinely free or just cheap. The four practical zero-cost options:

Option 1: Google Gemini (Recommended for Starters)

Gemini’s free tier on Google AI Studio gives you Gemini 2.0 Flash and Gemini 2.5 Pro at very generous request-per-minute limits with a 1M-token context window — long enough to dump your entire repo into a single prompt for most projects.

Get a free key at aistudio.google.com
In Cline settings, choose provider Google Gemini
Paste the key
Pick model gemini-2.5-pro (best for planning) or gemini-2.0-flash (faster, cheaper if you flip to paid)

For most personal projects, Gemini’s free tier is enough to keep Cline running indefinitely with no card on file.

Option 2: OpenRouter Free Models

OpenRouter aggregates dozens of providers behind one OpenAI-compatible endpoint, including a tier of :free models you can call without spending credits.

Sign up at openrouter.ai and copy your key
In Cline settings, choose provider OpenRouter
Paste the key
In the model search, type :free and pick a strong free model like deepseek/deepseek-r1:free or meta-llama/llama-3.3-70b-instruct:free

OpenRouter’s free tier rate limits are tighter than Gemini’s, but the variety is unmatched — you can switch between fifty different free models without changing keys.

Option 3: Ollama (Fully Local, Fully Free)

If you have a reasonable laptop and don’t want any cloud calls at all, Ollama runs models on your own GPU.

Install Ollama and pull a model: ollama pull qwen2.5-coder:14b
In Cline settings, choose provider Ollama
Set the base URL to http://localhost:11434
Pick the model you pulled

Quality drops below frontier models, but for boilerplate, file renames, and small refactors, a local 14B model is good enough — and zero tokens leave your machine.

Option 4: Together AI Free Tier

Together AI‘s -Free models include Llama 3.3 70B and DeepSeek R1 Distill 70B — both strong code models. Sign up, copy the key, choose the OpenAI-compatible provider in Cline, and point the base URL to https://api.together.xyz/v1.

Mixed Strategy: Plan with One, Act with Another

Cline lets you set different models for Plan and Act mode. A common pattern in 2026: use a frontier reasoning model (Gemini 2.5 Pro, Claude Opus, DeepSeek R1) for Plan mode, then switch to a fast cheap model (Llama 3.3 70B on Groq, Gemini 2.0 Flash) for Act mode. The plan is the expensive part of cognition; the execution is mostly mechanical edits.

A First Real Task: Add a Feature End-to-End

To make this concrete, here’s a typical Cline session for adding a “dark mode toggle” to a React app. The user types one prompt; everything else is Cline.

Prompt: “Add a dark mode toggle to the navbar. Persist the choice in localStorage. Use the existing Tailwind dark: variants — don’t introduce a new theming library.”

In Plan mode, Cline:

Reads tailwind.config.js, confirms darkMode: 'class' is set (or proposes enabling it)
Reads src/components/Navbar.tsx
Searches the codebase for any existing theme context
Writes a plan: add a useDarkMode hook, modify Navbar to render a toggle button, add a small effect that syncs the dark class on document.documentElement

You read the plan. If it looks right, you flip to Act mode. Cline:

Creates src/hooks/useDarkMode.ts — pauses, shows you the diff, waits for approval
Edits Navbar.tsx — pauses, shows the diff, waits for approval
Runs pnpm run dev in the terminal — pauses, asks before executing
Opens http://localhost:5173 in the built-in browser
Screenshots the navbar, clicks the new toggle, screenshots again, confirms the page background switched
Reports done with a list of files changed and the cost (e.g. “$0.04, 18,200 tokens”)

The full task is fifteen minutes of mostly autonomous work. You stayed in the loop at the four moments that matter (plan, two diffs, terminal). For senior engineers used to writing every line, this feels strange the first time and indispensable by the third.

MCP: Giving Cline Superpowers

Cline’s MCP support is what lets it reach beyond the file system. Three useful servers to install on day one (all from the Cline marketplace):

filesystem — read/write outside the open workspace, useful for cross-repo refactors
github — open issues, file PRs, comment on existing PRs without leaving the editor
playwright — drive a real browser to reproduce user-reported bugs against your dev server

To install one, click the MCP icon in Cline’s panel, search the marketplace, and click Install. The server runs as a local subprocess; no cloud connection unless the server itself needs one.

Custom MCP servers — anything you’ve built or anything from the wider MCP ecosystem — drop in just by adding their config to ~/.cline/mcp.json:

{
  "mcpServers": {
    "my-postgres": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-postgres", "postgres://localhost/dev"]
    }
  }
}

After a reload, Cline can run read-only SQL against your dev database without you copy-pasting schemas into the chat.

Cost Comparison: Cline + Free API vs Cursor / Copilot

Concrete monthly costs for a developer who uses an AI agent for, say, 60 hours of coding:

Setup	Monthly Cost	Model Quality	Notes
Cline + Gemini 2.5 Pro free tier	$0	Frontier	Hits rate limits at high usage; works for most solo work
Cline + OpenRouter free models	$0	Strong open	Tighter limits but huge model variety
Cline + Ollama Qwen2.5-Coder 14B	$0	Mid	Local, no cloud calls, no rate limits
Cline + Anthropic Claude Sonnet (paid)	~$10–40	Frontier	Pay only for what you use; transparent per-task
Cursor Pro	$20	Frontier (Claude/GPT)	Predictable; unlimited slow model, capped fast models
GitHub Copilot Individual	$10	Frontier (GPT-4.1)	Strong autocomplete, weaker agent UX
Cursor Pro + Cline as backup	$20	Frontier	Both options available; Cline catches what Cursor misses

The honest answer: if you bill clients for engineering time, $20/mo for Cursor pays for itself in the first hour. If you’re a hobbyist, student, or open-source maintainer, Cline + a free API tier gets you 80% of the experience at $0/mo. The two aren’t mutually exclusive — Cursor is itself a VS Code fork, so you can install Cline inside Cursor and have both available.

Cline vs Aider vs Continue.dev

The free open-source AI coding agent space in 2026 has three credible contenders. A quick decision matrix:

Project	Surface	Best For	Weakness
Cline	VS Code extension	Visual workflows, browser verification, MCP-heavy tasks	Heavier UI; needs VS Code
Aider	Terminal CLI	Power users on the command line, Git-aware refactors	No GUI; less hand-holding for newcomers
Continue.dev	VS Code & JetBrains	Enterprise teams that want shared config + autocomplete	Less autonomous than Cline; more like Copilot

If you live in VS Code and want full agent autonomy, Cline. If you live in tmux and want every change tied to a Git commit, Aider. If you need a team-shareable autocomplete plus chat, Continue. None of these is wrong; they fit different working styles.

Tips for Keeping Cost (and Frustration) Low

Use Plan mode aggressively. A 2,000-token plan is cheaper than a 20,000-token wrong-direction execution.
Add a .clineignore file so Cline doesn’t accidentally read node_modules, lock files, or build outputs into context.
Pin the model per-task. Use a small fast model for find-and-replace work; reserve the frontier model for design and debugging.
Cap with maxRequests. Cline has a per-task request limit that stops runaway loops — set it to 30 for most tasks.
Approve diffs incrementally. If a diff looks wrong, reject and explain in one sentence. Cline rewrites the diff much faster than rolling back later.
Pair with Ollama for repetitive tasks like generating tests for already-written functions; the local model is “free” tokens.

FAQ

Is Cline really free?

The Cline extension is free under Apache 2.0. The model calls are not — you pay whichever provider you connect (or pay nothing if you stay within a free tier or run Ollama locally). There’s no Cline-the-company subscription gate.

Does Cline work in Cursor or Windsurf?

Yes — both are forks of VS Code, and Cline installs cleanly inside either. Some users actually run Cursor as their editor and Cline as a second agent for tasks they’d rather hand off entirely.

Can Cline read my whole codebase?

It reads files on demand using a search-and-grep flow rather than embedding the entire repo. That keeps context windows honest and means you don’t need a vector database for it to work. For very large repos, pair it with a model that has a long context window (Gemini 2.5 Pro at 1M, Claude Sonnet at 200K).

Will Cline silently delete my files?

No. Every file write, terminal command, and browser action requires explicit approval before it runs (this is the default and changing it is a deliberate setting). The agent shows you the diff or the command before you click Approve.

Can I use Cline offline?

Yes — point it at Ollama or LM Studio running locally. Once the model is pulled, Cline does not need a network connection.

Does Cline support tool use / function calling?

Yes, both natively (its built-in tools for files, terminal, browser) and via MCP servers. Models that don’t support function calling natively still work — Cline uses a structured prompt format underneath.

What’s the difference between Cline and Roo Code?

Roo Code is a popular fork of Cline with an additional set of “modes” (Architect, Code, Ask, Debug) and slightly different UI conventions. Functionally similar; pick whichever interface you prefer. Both are free and open source.

Does Cline phone home or collect telemetry?

The extension itself sends only opt-in anonymous usage telemetry; the model calls go directly from your machine to whichever provider you configured. There is no Cline-operated proxy in the path.

When to Use Cline vs Alternatives

You want a free, transparent AI coding agent and don’t mind wiring an API key → Cline + a free model
You want zero setup and predictable monthly cost, willing to pay $20 → Cursor
You live in a terminal and want every change committed → Aider
You want only autocomplete plus a chat box → GitHub Copilot or Continue.dev
You want to plug your own MCP servers into the agent loop → Cline (best-in-class MCP UX)
You want to run everything locally with no cloud calls → Cline + Ollama

Use Cline with OpenClaw

OpenClaw is an AI agent platform for orchestrating multi-step automated workflows. Cline plays well at the seam between human-in-the-loop coding and fully autonomous OpenClaw flows.

A useful split: OpenClaw runs the long-running unattended jobs (nightly dependency updates, regenerating SDK clients from a changed OpenAPI spec, checking the build on multiple Node versions). Cline handles the human-in-the-loop work where you actually want to read every diff before it lands. The two share the same model providers — connect both to the same OpenRouter or Together AI key, and you have one billing surface for everything.

A concrete example pipeline: an OpenClaw cron job watches a third-party SDK for new releases, downloads the new version, runs your test suite against it, and on failure files a GitHub issue with the failing test and stack trace. The next morning, you open the issue inside Cline (“fix issue #483”), and Cline does the actual fix work with you supervising the diffs.

Final Verdict

Cline is the right default in 2026 for any developer who already has a free AI API key and wants a serious coding agent without paying a subscription. The Plan/Act split is genuinely better UX than the implicit modes other agents use. Native MCP support means it grows with the ecosystem instead of getting locked into one set of built-in tools. And because the provider is your choice, you can pick the cost/quality point that matches the task and switch the moment a better model lands.

Cursor and Copilot are still excellent products — for some teams the fixed monthly cost and curated model selection is exactly what’s wanted. But Cline is the option that makes “AI coding agent” available to anyone with a laptop and a free API key, with no gatekeeping and no contract. Install the extension, point it at Gemini, give it a small task, and decide for yourself.

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