Noesion Radarnoesion.ai
Release2026-10-29

Vercel updated the fx harness adapter for the AI SDK’s HarnessAgent. The harness and model requests now run on the host. Filesystem and shell operations remain in the sandbox. Sandbox setup is simpler because fx no longer needs installing inside it. Model credentials stay on the host. Built-in tool filtering is now available. Mid-turn steering can send new instructions during a turn. Structured output can generate schema-matching responses. Image tool results can return images to the model. Sessions can be saved and resumed in a new host process.

What changed

The harness and model requests ran in the sandbox alongside filesystem and shell operations.

What it unlocks

Running the harness and model requests on the host while keeping filesystem and shell operations in the sandbox.

What you need to act on it

  • update to the latest version of @ai-sdk/harness-fx

Sources

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