Reflection unveils Beam, its first open-weight model: 501B MoE (23B active) for coding and agents, 80.9% SWE-bench Verified, Apache 2.0 weights due this month
On Oct 5 Reflection AI introduced Beam, a sparse MoE with 501B total and 23B active parameters for coding, reasoning and agentic work. It was pretrained on 23.8T tokens, then put through a four-week high-compute RL run on 10.5K GB300 GPUs (100M+ rollouts), with 1M-token context. Reflection says it is competitive with GLM 5.2 and approaching Qwen 3.8-Max on coding and agentic tasks, matching GLM-5.2 on reasoning with 3–4x less inference compute. It is in final red-teaming with early-access signup only; weights, tech report and model card ship this month under Apache 2.0.

- •Scale: sparse MoE, 501B total / 23B active, 52 layers, interleaved local+global attention, 1M-token context
- •Self-reported scores: SWE-bench Verified 80.9, Terminal Bench v2.1 80.1, MCP Atlas 78.7, GPQA Diamond 90.5, AIME 2026 97.8, HLE (no tools) 36.2
- •RL run: 10.5K NVIDIA GB300 GPUs for four weeks, 100M+ rollouts up to 256K context, ~1.3B sandboxes, ~1M environments
- •Efficiency: GLM-5.2-level reasoning scores with 3–4x less inference compute; reasoning-effort parameter trades length for quality
- •Availability: in final red-teaming with early-access signup; Apache 2.0 weights, tech report and fine-tuning/eval stack due this month


