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Documentation Index

Fetch the complete documentation index at: https://docs.arkor.ai/llms.txt

Use this file to discover all available pages before exploring further.

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infer

Inside onCheckpoint, the SDK hands you a function called infer. Calling it runs an inference request against the just-saved checkpoint and returns a raw Response. This is the path that lets you evaluate a half-trained model before the full run finishes. 
onCheckpoint: async ({ step, infer }) => {
  const res = await infer({
    messages: [{ role: "user", content: "I can't log in." }],
  });
  console.log(`step=${step}`, await res.text());
}
The default response is an SSE stream (the same shape Studio’s Playground consumes). Pass stream: false if you want a single JSON body instead: 
const res = await infer({ messages, stream: false });
const data = await res.json();
infer is only available on CheckpointContext. There is no top-level export of it; the callback argument scopes the call to the right job and step automatically.

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Common scenarios

  • Sanity check. Compare step-50 and step-100 outputs against a fixed prompt.
  • Custom early-stopping. Combine with abortSignal + cancel() to stop a run that has gone off the rails. See the Early stopping recipe.
  • Live preview. Forward the checkpoint output to Slack or your own review queue.

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Reference

For the full InferArgs shape, the streaming-vs-JSON tradeoffs, the SSE frame format, the constraints on retargeting, and pointers for decoding the SSE delta stream, see the infer reference.