Ultramarine 1 Flash beats Claude Fable 5 on four of six benchmarks at $0.13 per task

San Francisco startup Paper Instruments unveiled Ultramarine 1 Flash, a model post-trained for $300,000 on top of Z.ai's open-weight GLM-5.3 Flash. It outperformed Claude Fable 5 on four of six knowledge-work benchmarks at roughly one-sixty-third of Fable 5's cost per task, and scored 62.9 on UW JobBench, 17 points above the prior top result. Open weights for independent verification are expected within two weeks of the October 14 launch.

• Post-training on GLM-5.3 Flash cost $300,000
• Cost per task is about 1/63 of Claude Fable 5
• UW JobBench score of 62.9, 17 points above prior best
• Open weights expected within two weeks of launch