fx :Tiny, open, native coding agent.

# fx - Tiny, open, native coding agent Source: [https://fx.sh/](https://fx.sh/) Tiny, open, native coding agent\. v0\.0\.36\.39mibstatus:experimentaluse at your own risk, we will be making frequent changes This demo runs the full fx CLI as WebAssembly compiled with the Zig toolchain\. Networking is delegated to browser[`fetch`](https://fx.sh/docs/lib/host-integration#network-requests), and every SDK aspect is configurable in the[docs](https://fx.sh/docs/lib)\. fxis a coding agent harness and CLI written in Zig, optimized for research and embeddability as part of larger systems\. It focuses on minimalism and performance across the board, from system prompt design, to its tools, feature set, and 6\.39mib binary\. 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\. It's open source \(Apache\-2\.0\), model\-agnostic, and suitable for both local and cloud inference\. ## Tiny ~6mb binary Designed for instant installation and embedding in resource constrained environments and agent sandboxes\. ## Instant time to prompt fx cold starts in10µsand does no unnecessary work or I/O prior to accepting user input, making it ideal for programmatic use\. ## Wasm support Optimal fx\.wasm builds produced by the Zig toolchain, which further reduce fx's size, making the network stack pluggable\. ## Minimal memory footprint fx contributes single\-digit megabytes of memory baseline, allowing you to pack many instances in one machine\. ## Shell\-like UI and ergonomics fx preserves scroll history by default, produces minimal output, and makes sparing use of complex TUI or paints ## Context efficient Minimal system prompt and tools, to save on token costs and to yield optimal time\-to\-first\-token performance \(TTFT\)\. ## Embeddable and extensible Small core, extended via skills, plugins, MCPs, with a Unix\-like philosophy to extensibility\.