Reflection's Beam is a 501B open-weight model for coding agents: where it fits and what it costs to run
Reflection released the weights of Beam, a 501B-parameter open-weight model with 23B active parameters, under Apache 2.0 on 16 October 2026. Artificial Analysis scores it 30 on its Intelligence Index, second among US open-weight models, and says K2 Horizon, one point ahead, uses about twice the output tokens.
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