Freebuff

Why it's ranked here

The price is the headline: a working terminal coding agent with no subscription, no key and no setup. What backs it is a serious engine. The repository is the full Codebuff monorepo, with a reusable SDK, a published agent runtime and an end-to-end test suite covering startup, code edits, terminal commands and ad behaviour. The security writing is unusually candid: the docs state that downloaded agent code runs without a sandbox, then describe the publisher allowlist and per-folder consent prompt built to contain it. The cost is privacy, and the README states it plainly rather than hiding it.

What's good

The default agent is deliberately small: eight core tools, one loop, and a short system prompt that tells it to match project conventions, make the fewest changes, run the typecheck and tests, and avoid pushes or resets unless asked. Cloning a hostile repository is handled with care: project-level agents and tool-server configs do not run until you answer a yes or no prompt, and CI runs skip them unless you opt in. Edits cut off mid-generation are refused rather than patched, so a half-written file never lands on disk. Environment files are blocked from agent reads by default.

Tradeoffs

Free is paid for with your data. The README says prompts and messages may be analysed to personalise ads, some models may use submissions for training, and one beta model comes from an anonymous provider that retains prompts. Users outside supported regions or on a VPN get limited access and a smaller daily allowance. The model menu changes often: the README notes a retired DeepSeek model, and the CLI agent tied to it still references that model. Licensing is inconsistent, with the root manifest declaring Apache 2.0 while the Freebuff and SDK readmes say MIT. Agent folders you approve once stay trusted even if their contents later change.

How to use it well

Use it for everyday edits on personal or open-source code where cost matters more than confidentiality: bug fixes, small features, refactors and test runs from the terminal. Pick an unmetered model for long sessions so they do not eat your allowance. Keep proprietary or regulated code out, since prompts feed ad personalisation. Answer no to the trust prompt in any repository you did not write. Developers who want to build their own agents should look at the Codebuff SDK, which needs a paid Codebuff key. Freebuff does not cover teams needing a no-retention guarantee.

Observed

License

Apache-2.0 in the root package.json; MIT stated in freebuff/README.md and sdk/README.md

Language and runtime

TypeScript monorepo, Bun runtime and package manager

Install

npm install -g freebuff; source build with Bun from a clone of the repository

Interfaces

Terminal CLI (OpenTUI + React), JS/TS SDK published as @codebuff/sdk, desktop, web and cloud products

Funding model

Text ads; README states prompts and messages may be analysed to personalise ads

Access tiers

Full access in supported regions; limited model set and smaller daily allowance outside them or over VPN

Agent code isolation

Registry agent step functions run unsandboxed; gated by a trusted-publisher allowlist and per-directory consent prompt

Tests

End-to-end suites declared in freebuff/package.json, including startup, code-edit, terminal-command and ads-behavior