Thinking Machines Lab, the AI startup founded by former OpenAI CTO Mira Murati, released its first in-house AI model Wednesday morning, called Inkling. Unlike flagship models from OpenAI, Anthropic, or Google, it is open-weight, meaning outside developers can download and modify it. Inkling is a mixture-of-experts system with 975 billion total parameters, though it draws on about 41 billion for any given task. It was trained on 45 trillion tokens of text, image, audio, and video, and reasons natively across all four, though its outputs are currently limited to text. The model is Thinking Machines Lab’s first public proof point after a year and a half spent building AI infrastructure largely out of public view. Inkling is designed to give calibrated answers, including flagging uncertainty, and lets users dial “thinking effort” up or down. On one benchmark, the company says Inkling uses a third as many tokens as Nvidia’s Nemotron 3 Ultra to hit the same coding performance. Thinking Machines does not claim Inkling is best-in-class, stating explicitly that it is “not the strongest overall model available today, open or closed.” The company is marketing Inkling less as a finished product than as a starting point for organizations to fine-tune through its platform, Tinker.