The fx adapter now runs the harness on the host

The fx adapter for the AI SDK's HarnessAgent now runs the harness and model requests in the same process as the application, using the libfx TypeScript library, while built-in filesystem and shell operations stay isolated in the sandbox. The rewrite removes the need to install fx inside the sandbox, run a sandbox bridge, or expose a sandbox port, and keeps model credentials on the host instead of forwarding them into the sandbox. It also adds built-in tool filtering, mid-turn steering, structured output, image tool results via toModelOutput(), and sessions that can be saved and resumed in a new host process; developers must update @ai-sdk/harness-fx to the latest version.

The fx adapter for the AI SDK’s HarnessAgent now runs the harness and model requests in the same process as your application. Built-in filesystem and shell operations remain isolated in the sandbox. The adapter uses libfx , the TypeScript library for fx. It no longer needs to install fx inside the sandbox, run a sandbox bridge, or expose a sandbox port. Model credentials stay on the host rather than being forwarded into the sandbox. The rewrite also adds: Built-in tool filtering: choose which built-in tools the agent can use Mid-turn steering: send new instructions while a turn is running Structured output: generate responses that match a schema Image tool results: return images to the model through toModelOutput Sessions can be saved and resumed in a new host process. Update @ai-sdk/harness-fx to the latest version to use the new adapter. Learn more in the fx harness documentation https://ai-sdk.dev/providers/ai-sdk-harnesses/fx .