Cline vs Roo Code in 2026: Which Open Source AI Coding Agent Should You Actually Run?

Short answer: run Roo Code if you want to shape the agent yourself, define custom modes, pin different models to different jobs, and live close to the newest features. Run Cline if you want a stable, well-documented default that behaves predictably and that you can hand to a teammate without a 20 minute explanation. Both are genuinely good. The gap between them is smaller than the gap between either one and the model you point it at.

Now the caveat that most comparisons skip: neither Cline nor Roo Code is a terminal-native agent. Both are editor extensions first, built for VS Code and its forks. They run commands in your terminal, but the agent itself lives in a sidebar. If your actual requirement is "an agent I drive from a shell over SSH, in tmux, inside a container," that is a different product category, and I cover it at the end. If your requirement is "an open source agent that edits my repo and does not send my code anywhere I did not choose," these two are the right shortlist.

They share a bloodline, which is why this comparison is hard

Roo Code started as a fork of Cline. That is not a knock on either project, it is the most important fact for understanding them. The core loop is the same: the agent reads files, proposes diffs, asks to run commands, and iterates on the results. The approval model is the same shape. Both connect to essentially any provider you want, including Anthropic, OpenAI, Google, OpenRouter, and local models through Ollama or LM Studio. Both speak MCP, so your existing servers work in either one.

So when someone tells you one is dramatically better, be skeptical. They diverged on philosophy, not on capability.

Where they actually differ

Control surface. Cline centers on a two-mode workflow: plan first, then act. It is a clean idea and it maps to how most people already work. Roo Code went the other direction and shipped a mode system, with distinct built-in modes for coding, architecture, asking questions, and debugging, plus the ability to define your own with custom instructions, custom tool permissions, and a specific model per mode. That last part is the real feature. Assigning a strong reasoning model to planning and a cheaper, faster model to mechanical edits is the single most effective cost lever available in either tool, and Roo Code makes it a first-class setting.

Roo Code also lets you override the system prompt outright. That is powerful and dangerous in equal measure, which is roughly how the project frames it. Cline does not hand you that particular knife.

Recovery when it goes wrong. Agents go wrong. Cline's checkpoint system, which snapshots workspace state as the task progresses so you can roll back to a point before the agent made a mess, is the feature I would miss most switching away. Roo Code has comparable functionality. Test both against a task you expect to fail, because a rollback that works is worth more than three features that mostly work.

Release cadence. Roo Code ships faster and ships more experimental things. Cline moves more conservatively and has a company behind it, which shows up as steadier documentation and a more predictable upgrade path. Pick according to your tolerance for a Tuesday where an update changes behavior you depended on.

Context handling. Both auto-compact when the window fills, and both are at their weakest right at that moment. Summarization is where agents lose the thread of what they were doing. This is not a differentiator so much as a shared limitation, and the practical response for both tools is identical: keep tasks small enough that they never hit the boundary.

The cost conversation nobody has upfront

Bring your own key means you see the bill. Both tools work by putting real file contents into the context window, repeatedly, across many turns. A single "refactor this module" task on a large repo can cost more than a full day of a flat-rate subscription tool. That surprises people badly in month one.

Three things that actually help, in order of impact:

1. Use a provider and model with prompt caching, and confirm in your provider dashboard that cache hits are actually registering. Assume nothing here.
2. Split model duties. Expensive model for planning, cheap model for edits.
3. Keep tasks narrow. "Add validation to this one endpoint" costs a fraction of "clean up the API layer," and produces a diff you can actually review.

If you would rather have a predictable monthly number than a metered bill, that preference alone points you toward a subscription-based agent instead. It is a legitimate reason to choose neither of these.

Privacy: what actually leaves your machine

This is why I use tools in this category at all. With BYO key, your code goes to the model provider you selected and nowhere else, under that provider's terms. There is no intermediate service holding your repository, which is the meaningful distinction versus most hosted coding agents.

Two things to check on install rather than assume. First, telemetry: both projects ship optional usage telemetry, and both let you turn it off, so go find the setting and set it deliberately. Second, if either tool offers a hosted or managed provider option, understand that choosing it changes the data path. The open source client does not make the backend you pointed it at private.

One underused advantage of open source agents: you can read the system prompt. It is in the repository. Thirty minutes reading how the agent is actually instructed to behave will teach you more about why it does the annoying thing it does than any amount of prompt fiddling.

If you truly want a terminal agent

Both projects have been moving toward command line and headless usage, and the current state changes fast enough that you should check the repository rather than trust an article. If terminal-native is a hard requirement today, look at Claude Code, Aider, or OpenCode. Aider in particular has been shell-first since the beginning and has a very different, git-centric working model that some people prefer outright.

Be honest with yourself about whether "terminal" means "I work over SSH on a remote box" or just "I like the aesthetic." Only the first one should change your decision.

The evaluation that beats any comparison table

Ignore feature lists, including mine. Spend one hour:

1. Take a real ticket from your own backlog. Not a toy. Something with ambiguity in it.
2. Run it in Cline. Then reset the branch and run the same ticket in Roo Code, with the same model.
3. Record three numbers. How many turns before the agent touched a file it should not have. What the provider dashboard says each run cost. What percentage of the final diff you kept without editing.

That third number is the one that matters. An agent that produces a diff you rewrite by hand is a slower way to write the code yourself.

What I run

I use Cline as the default because predictable beats clever when I am shipping, and I keep Roo Code installed for work where the mode system earns its keep, mostly larger changes where planning and editing genuinely want different models. Having both installed costs nothing. Neither project punishes you for hedging.

FAQ

Is Roo Code just an older fork of Cline? No. It started as a fork and has since diverged substantially in its mode system, configurability, and release philosophy. Treat it as a sibling project, not a stale copy.

Which one is cheaper to run? Neither is inherently cheaper, because the cost is dominated by the model and the size of the task. Roo Code's per-mode model assignment gives you a slightly better lever for controlling spend, if you actually configure it.

Can I use these with a fully local model? Yes, both connect to Ollama and LM Studio. Expect a real quality drop on multi-step agentic tasks compared to frontier models. For "no code leaves this machine, ever" requirements it is still worth it. For general daily work, most people find it frustrating.

Do I need both installed? No, but there is no penalty for it. They coexist fine in the same editor and read the same repository.

Are they safe to run with auto-approve enabled? Auto-approving file edits inside a git repository with clean commits is reasonable. Auto-approving arbitrary terminal command execution is not, unless you are inside a container you are willing to lose. Set that boundary on day one, before you get comfortable.