fx - Tiny, open, native coding agent<br>Tiny, open, native coding agent.<br>$ curl -fsSL https://fx.sh/setup.sh | bashcopied<br>v0.0.3 路 6.39mib 路 status: experimental (i)use at your own risk, we will be making frequent changes
This demo runs the full fx CLI as WebAssembly compiled with the Zig toolchain.<br>Networking is delegated to browser fetch, and every SDK aspect is configurable in the docs.
fx
饾拠x v0.0.3 路 Run /help for commands
auto 路 glm-5.2(i)This demo is available in browsers with WebAssembly JSPI support, like Safari 27+ and Chrome.This demo runs fx in WebAssembly with a browser workspace powered by just-bash. Install fx for the full tool suite on your own files.
fx is a coding agent harness and CLI written in Zig, optimized for research and embeddability as part of larger systems.<br>It focuses on minimalism and performance across the board, from system prompt design, to its tools, feature set, and 6.39mib binary.<br>For end users, its CLI output style and form factor aims to be closer to a Unix shell than a heavy "IDE in the terminal" TUI.<br>It's open source (Apache-2.0), model-agnostic, and suitable for both local and cloud inference.
Tiny ~6mb binary<br>Designed for instant installation and embedding in resource constrained environments and agent sandboxes.
Instant time to prompt<br>fx cold starts in 10碌s and does no unnecessary work or I/O prior to accepting user input, making it ideal for programmatic use.
Wasm support<br>Optimal fx.wasm builds produced by the Zig toolchain, which further reduce fx's size, making the network stack pluggable.
Minimal memory footprint<br>fx contributes single-digit megabytes of memory baseline, allowing you to pack many instances in one machine.
Shell-like UI and ergonomics<br>fx preserves scroll history by default, produces minimal output, and makes sparing use of complex TUI or paints
Context efficient<br>Minimal system prompt and tools, to save on token costs and to yield optimal time-to-first-token performance (TTFT).
Embeddable and extensible<br>Small core, extended via skills, plugins, MCPs, with a Unix-like philosophy to extensibility.
Model and provider agnostic<br>Designed to work with local models, gateways, direct provider API access or subscriptions.