Reflection launches Beam: 501B open-weight MoE trained on 23.8T tokens with 100M+ RL rollouts

gethackteam · x · 2026-10-06

Reflection announced Beam, its first open-weight model: a sparse MoE with 501B total / 23B active parameters, built for coding, reasoning, and agentic workloads.

Training: pretrained on 23.8T curated tokens (web + licensed proprietary data), matching or beating similar-sized open base models; a high-compute RL run generated 100M+ rollouts on 10.5K NVIDIA GB300 GPUs over 4 weeks.

Positioning: advances the Western open-weight frontier on coding and agentic tasks — competitive with GLM 5.2 and approaching Qwen 3.8-Max, though frontier open models like Kimi K3 stay ahead on raw capability; Beam's edge is inference-time efficiency. Benchmark charts cover agentic coding/terminal, reasoning, and tool calling.

Rollout: final red-teaming underway, early access open now; weights, tech report, model card, and developer artifacts ship later this month.

Related event: Reflection AI Debuts Beam, a 501B-Parameter Open-Weight Model(20 posts)→

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