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Mercor: +8.2 pp software-task pass rate from a few hundred expert tasks

Mercor (expert data) reported this on 15 Oct 2026 in company self-report (source). It belongs to the learning loop layer.

What they built

NVIDIA Nemotron 3.5 Super post-trained on a few hundred expert tasks per domain (legal, software engineering, accounting) from Mercor's APEX work environments.

The result

On held-out tasks, versus the base model: legal rubric score +6.7 pp, software full-pass +8.2 pp (26.6% to 34.7%), accounting rubric score +7.3 pp.

The number covers APEX benchmarks; measured against the base model; a comparison with frontier models is not reported.

“With only a few hundred training tasks per domain, that's a meaningful gain on work the model had never seen,” Mercor said.

The layer: The learning loop

Reviewed corrections are kept as test cases and later used to train models.

  • A log of every correction and who reviewed it
  • Eval sets that grow from reviewed corrections
  • New versions, then post-trained models, from that signal

Read the guide to the learning loop.

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