Muse Spark Open model card

Meta Superintelligence Labs released the Muse Spark Open model card. The model is an open-weight MoE model with 816B total parameters and 42B active parameters, a 1M token context window, natively multimodal, and designed for coding and agent tasks. The model card states that this open-weight version adds safety post-training to improve resistance to abuse when used standalone without system guardrails, and recommends deploying it in AI systems with additional guardrails. Safety evaluations show the model refuses 99.2% of jailbreaks on internal benchmarks for cyber abuse, and 94.8% on the combined PolyGuard, RedCode, and CyberBench 2024 sets; on SecureBio's BioTIER refusal benchmark it refuses over 98% of harmful requests. The model is licensed under the Muse Model License; companies with annual revenue over $20 million that offer the model as a service must sign a separate agreement with Meta.