fx is now available in the AI SDK harness layer
Vercel's AI SDK harness now runs fx through the same HarnessAgent API used for other coding agents, reducing the need for another bespoke integration.
The AI SDK harness layer adds **fx** through the official **@ai-sdk/harness-fx** adapter. It connects over the Agent Client Protocol using @ai-sdk/harness-acp.
If your app already targets HarnessAgent, treat fx as another swappable agent backend rather than building an fx-specific execution path.
The AI SDK harness layer adds **fx** through the official **@ai-sdk/harness-fx** adapter. It connects over the Agent Client Protocol using @ai-sdk/harness-acp. If your app already targets HarnessAgent, treat fx as another swappable agent backend rather than building an fx-specific execution path. The announcement describes interface compatibility, not behavioral parity, performance, or which fx capabilities survive the common abstraction.
fx expands HarnessAgent’s official backend set and confirms that ACP is serving as the portability boundary for coding runtimes. Applications already built to that interface gain another runtime choice without a separate execution path, but the adapter does not make fx behavior interchangeable with other agents; capability coverage, controls, security, and runtime semantics still require fx-specific validation.