The AI SDK harness layer now supports fx, Vercel's lightweight, open-source coding agent. The harness layer provides one API for running coding agents in your application, so you can add fx without building a separate integration.

Configure HarnessAgent with the official @ai-sdk/harness-fx adapter:

import { HarnessAgent } from '@ai-sdk/harness/agent';
import { fx } from '@ai-sdk/harness-fx';
const agent = new HarnessAgent({
  harness: fx,
});

The @ai-sdk/harness-fx adapter connects to fx over the Agent Client Protocol (ACP) using @ai-sdk/harness-acp.

fx joins Claude Code, Cline, Codex, Cursor, Deep Agents, Grok Build, OpenCode, and Pi in the list of supported harnesses.

Read the fx harness documentation to get started.