fx Enters T3 Code, and Coding Agents Start Competing for the Console

Vercel's changelog has an update: the open-source coding agent harness fx is now a built-in provider in T3 Code. In T3 Code, it works on web, desktop, and mobile, both Supervised and Auto modes are available, and previously configured models and skills continue to work.

Let's clarify two terms first. fx is Vercel's open-source coding agent harness, which can be understood as a layer that wraps together models, tools, permissions, and execution flow. T3 Code is an open-source coding agent control plane used to manage coding sessions and also allows agents like fx to be added as providers. After this update, users no longer have to run fx only in the terminal; they can start sessions, choose modes, and switch models in one place in T3 Code.

When Chris Tate reposted it, he wrote fx in the cloud and also said 'Nice ship @z0oks'. The original Vercel Developers tweet focused on three things: across web, desktop, and mobile; compatibility with existing models and skills; and integration into T3 Code as a built-in provider. This combination solves the hassle of multiple endpoints and multiple configurations. You don't need to reconfigure models and skills just to switch interfaces.

Usage isn't complicated. First install fx, then set up a model provider. Then download T3 Code, open Settings > Providers > Add provider, and add fx. The changelog puts it very briefly; those are the steps.

There were two kinds of reactions in the replies. Jeremy Bauman asked whether it's possible to use only ZDR models. This question points to data retention and model choice, but the changelog does not directly answer it. Saumya Verma said that now every tool is turning into an agent harness. It sounds like a joke, but compared with this update it's not far off. Before, you installed plugins for an editor; now you stuff an agent into the console as a provider. The name has changed, but the contested position hasn't: who manages sessions, models, and permissions.

T3 Code is positioned more like a control plane, a place to manage sessions and providers. Once fx goes in, cross-platform support is only a surface change; what really changes is that the entry point for coding agents is being pulled toward the console. For developers this is good: more choices, and configuration is centralized. The cost is that permission boundaries, model policies, and session management become more worth watching. The ZDR question is an example.

The source page lists author Andrew Gadzik and contributors Pranit Sharma, Esteban Suárez, and Ben Sabic.

For more details, see Vercel changelog and fx docs.