Full-parameter SFT of NVIDIA Nemotron-3-Super-120B (hybrid Mamba-2 + Latent-MoE, top-22 routing over 512 experts) for the Rovo Chat long-horizon (LH) orchestrator task: given a multi-turn conversation + a tool catalog, decide whether to answer in text or call the right tool with the right arguments.

Results — 725-example LH-orchestrator answer-accuracy (Claude-Opus-4.8 judge)

model	overall	text	tool
This SFT (iter_001)	70.5%	78.9%	46.8%
base Nemotron-3-Super-120B (think_off)	68.0%	77.2%	42.1%
Qwen3-32B	71.0%	85.4%	30.5%
Gemma-4-31B	84.8%	95.9%	53.7%

Beats the base model on all three metrics (+2.5 overall, +1.7 text, +4.7 tool). The largest gain is on tool-calling — the base's weakest dimension — and this model's tool accuracy also exceeds Qwen3-32B's.

Training

Stack: Megatron-Core 0.16.1 + Megatron-Bridge (full-parameter SFT, not LoRA).
Recipe: 1 epoch (366 steps, ~2.1 h), LR 2e-6 cosine (~5% warmup), weight_decay 0.1, GBS 16, bf16; train loss 1.47→1.20 (stable).
Parallelism / memory: TP=8 / EP=8 / DP=4 on 4×H200; FlashAttention 2.8.3, MoE expert capacity_factor=1.5, full activation recompute, CPU-offloaded distributed optimizer.
Data: Rovo Chat Orchestrator SFT v3 (high-quality prod traces, CSR>90), 5,849 examples after prep.

Known limitation (next-iteration target)

The 124.5B top-22/512-expert MoE + the ~11K-token Rovo system prompt cap full-parameter training to seq=16384 on 4×H200, so each example was right-anchored-truncated to system + a few tools + recent context + the final assistant turn — the full ~46K-median agentic traces do not fit. The model still improved over base; remaining errors (spurious/missed/wrong tool) should shrink with the full-length context that a larger GPU budget would unlock.

Fine-tuned on internal Atlassian Rovo production data.

tzchen07/Nemotron-3-Super-120B-rovochat-orchestrator-sft-iter001

Nemotron-3-Super-120B — Rovo Chat Orchestrator SFT (iter_001)

Results — 725-example LH-orchestrator answer-accuracy (Claude-Opus-4.8 judge)

Training

Known limitation (next-iteration target)

tzchen07/
Nemotron-3-Super-120B-rovochat-orchestrator-sft-iter001