Unofficial · not affiliated

fx

A tiny, open, native coding agent.

Durable turns run on Vercel.

Tiny CLI

~5.97 MiB Zig binary. Vendor (fx.sh): “5.97 MiB binary.” Vendor (fx.sh/about): “around 6 MiB.” Harness and CLI in Zig, Apache-2.0, model-agnostic. This page did not measure the file.

fx.sh Vendor

Embed with libfx

Vendor (fx.sh/about): libfx on npm embeds fx in Node.js or WebAssembly hosts. Docs: npm i libfx.

fx.sh/about Vendor

Durable turns on Vercel

Docs: export const POST = agent.wakeHandler() on queue topic __libfx_wkf_workflow_session (queue/v2beta). After a crash, Vercel Queues redelivers the turn, and a new function continues it from its last saved step.

vercel.com/docs/agent-harnesses/fx Docs fx.sh/docs/lib/durability Docs

Drill

Story frame · Maya Chen, platform engineer. Before: a support refund dies mid-flight, and a blind restart can charge twice. Drill: a libfx session, wakeHandler(), topic __libfx_wkf_workflow_session, and an idempotent tool. Kill the Function, resume from the last step, settle the refund once. Not a measured production incident.

wakeHandler() · __libfx_wkf_workflow_session

Idle

Settled refunds

0

executionId

—

Step log

  1. No steps yet. Start the turn to run the drill.

Quoted mechanism from Vercel’s fx docs and fx.sh/docs/lib/durability. Order ORD-1842 and executionId exec_9c2e are drill fixtures. Nothing here calls libfx, Vercel, or a payment API.

Install

Documented on fx.sh. Copy the line, or open the script host. This page does not run it.

curl -fsSL https://fx.sh/setup.sh | bash
fx.sh/setup.sh
fx.sh github.com/vercel-labs/fx Durable turns on Vercel