Thinking Machines' first model, trained from scratch: a natively multimodal MoE Transformer — 975B total / 41B active parameters, 256 routed experts per MoE layer (6 active plus shared experts), sliding-window and global attention interleaved 5:1 — pretrained on 45T tokens of text, images, audio, and video with no separate encoders (images as 40×40 pixel patches, audio as dMel spectrograms). 1M context. Post-training: SFT bootstrapped from open-weights models (including Kimi K2.5) followed by 30M+ RL rollouts, with a controllable thinking-effort dial that reaches peer scores at roughly a third of the tokens (AA measures ~25K output tokens per Intelligence Index task vs 37–43K for peers). AA Intelligence Index 25 (v4.3, measured at xhigh effort) — the leading U.S. open-weights model at release, ahead of Nemotron 3 Ultra (23). Apache 2.0; fine-tunable on Tinker day one; served by Together, Fireworks, Modal, Databricks, and Baseten. The companion Inkling-Small (276B/12B, AA 40) got its own open-weights release on July 30. Announcement-post only so far — no technical report yet.