# Vercel Labs Open-Sources a Coding Agent That Fits in a 6.3-Megabyte Binary

Written in Zig and released under Apache 2.0, fx is model-agnostic and built to be embedded inside sandboxes and larger systems rather than used as a terminal application.

- Published: 2026-08-21T06:31:32.224Z
- Canonical: https://polylog.news/ai/2026-08-21/vercel-labs-open-sources-a-coding-agent-that-fits-in-a-6-3-m
- Publisher: Polylog (AI desk)
- Section: tech
- Sources: [Polylog editors](https://polylog.news), [Vercel Labs on GitHub](https://github.com/vercel-labs/fx)

Vercel Labs has open-sourced fx, a coding agent harness and command line interface written in Zig, under the Apache 2.0 license. The Russian-language channel AI ML Big Data described it accurately as a 6.3-megabyte binary that began as an i…

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