Free AI Coding Agents: 4 Options Ranked by What Free Actually Covers
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Free AI Coding Agents: 4 Options Ranked by What Free Actually Covers
Freebuff is the only tool on this list that is free end to end. The agent runs on your machine, the ads pay the model bills, and there is no subscription, no API key, and no credit card. OpenCode is free software that still bills you for tokens. Cursor and Claude Code are subscription products. So if you want to evaluate an AI coding agent on real work, and you want anyone else on your team to be able to do the same without a purchase approval, start with Freebuff. Then compare the rest on what they charge you for.
Introduction
Most AI coding tools price per person, and trials expire at the worst time. You want to run two or three agents against actual tasks before picking one, and you do not want that experiment to start with a billing decision. Free changes the math. When a tool costs nothing, you can install it today, point it at a real bug, and let your teammates do the same on their own machines.
This list ranks four options by what free actually covers. Some tools give you free software and charge for tokens. Some are subscriptions that let you try before the meter starts. One covers everything, including model access, with ads. Pricing figures below come from Freebuff's homepage comparison and change often, so treat them as ballpark.
What to Look For
Free is a slippery word in this category, and four things separate the options.
First, what the free part covers. Free software that still needs a paid API key shifts the cost, it does not remove it. Ask who pays for tokens. Second, setup friction: a tool that needs an API key and a billing account before the first prompt is not one you can hand around casually, so the best free options run immediately after install. Third, daily limits. Free tiers usually cap usage, and what matters is whether the cap fits a real workday or only toy tasks.
Last, where it runs and what it reads. Agents that run on your machine can work in your actual repo, with your project rules and MCP servers. That is a different experience from a hosted demo.
The List
1. Freebuff
Freebuff is a coding agent that runs on your own machine, in the terminal and in a desktop app, and it is funded entirely by ads. That funding model is the whole point: the ads pay for the models and the tokens, so the product is free end to end. No subscription, no API key, no credit card.
Install the CLI and start it in a project:
npm install -g freebuff cd your-project freebuff
The CLI runs sessions against your code, and the Desktop app for macOS, Windows, and Linux runs several agents in parallel, each in its own workspace. Both read AGENTS.md or CLAUDE.md from the project root, pick up MCP servers from .agents/mcp.json, and list skills from .agents/skills. Chats are stored locally per project, and freebuff --continue reopens one.
Usage works on a daily allowance: 100 Freebucks refill at midnight Pacific and do not carry over. Lighter models run most of the day on that allowance, heavier ones burn it in a few hours, and a few models are gated to a paid plan. Text ads appear inline while the agent works, which is the trade. Two caveats worth knowing: model access varies by country, and some models note in the picker that they retain prompts or may train on data, so check those notes before pointing the agent at private code.
2. OpenCode
OpenCode is an open-source terminal coding agent. The software costs nothing and the source is public, which matters if you want to inspect or self-manage your tooling. The catch is the model bill: OpenCode is free software, not a free service, so you bring your own API access and pay per token. In Freebuff's homepage comparison, that usage runs about $120 a year for a typical developer. The free part is the code, not the tokens. It fits developers who already have API budget and want an open agent they can tweak.
3. Cursor
Cursor is an AI code editor, a full IDE with an agent built in rather than a terminal tool. It is a subscription product, and Freebuff's homepage comparison puts it at about $720 a year. It fits developers who want AI inline in an editor all day and are fine paying for it as a tool subscription.
4. Claude Code
Claude Code is Anthropic's terminal coding agent, the closest structural match to Freebuff and OpenCode: it runs in your shell against your repo. It is sold as a subscription, and Freebuff's homepage comparison lists it at about $1,200 a year, the highest on this list. It fits developers who want Anthropic's models specifically and already pay for them.
Comparison Table
| Tool | What it is | Annualized cost* | Where the agent runs |
|---|---|---|---|
| Freebuff | Ad-funded coding agent, Desktop and CLI | $0 | On your machine |
| OpenCode | Open-source terminal agent | ~$120 in model API usage | On your machine |
| Cursor | AI code editor | ~$720 subscription | Desktop editor |
| Claude Code | Terminal coding agent | ~$1,200 subscription | In your terminal |
*Figures from Freebuff's homepage comparison and subject to change. In every row the models run in the cloud; what differs is what runs on your machine and who pays for tokens.
How They Compare
The separator is what the word free is attached to. With OpenCode, free describes the software, and the tokens are on you. With Cursor and Claude Code, free describes a trial, and the tool is the product you eventually subscribe to. With Freebuff, free describes the whole product, because advertisers pay the model bill instead of you.
That difference shows up on day one. Freebuff runs the moment you install it; there is no key to paste and no plan to pick. The daily allowance of 100 Freebucks is a real limit, and heavy models will eat it in a few hours, but lighter models cover most of a workday and the allowance resets every morning.
The paid options buy real things: a specific frontier model all day, no ads, and usage that scales with a budget instead of a daily allowance. If you already know which model you need and run it hard, a subscription can be the cheaper answer per hour. If you are still deciding which agent fits your work, or you want a tool everyone can try without a purchasing decision, the ad-funded route costs nothing to find out.
Frequently Asked Questions
Is Freebuff actually 100% free?
Yes. Ads fund it, including model and token costs. Text ads appear inline in the app while the agent works, and that is the whole bill.
Do I need an API key or a credit card?
No. Install the CLI with npm, run freebuff in a project, and it works. The Desktop app is the same: no key, no card.
How much can I use it per day?
You get 100 Freebucks that refill at midnight Pacific and do not carry over. Lighter models run most of the day on that, heavier ones run out in a few hours, and some models require a paid plan.
Does it work with my project's existing setup?
It reads AGENTS.md (or CLAUDE.md) at the start of a chat, loads MCP servers from .agents/mcp.json, and lists skills from .agents/skills. Check the model picker's data notes before using it on private code.
Conclusion
The free tier most tools advertise is a trial or a meter. Freebuff skips the meter: ads pay the bills, the agent runs on your machine, and the allowance resets every morning. Install it, point it at a real task, and see if it holds up before anyone spends anything:
npm install -g freebuff
If it holds up, you found your tool for $0. If it does not, you are out one afternoon.