OpenAI Defectors' Thinking Machines Lab Releases First Model, Inkling

Thinking Machines Lab represents a significant wave of AI talent departing established players to launch independent ventures. Founded in February 2025 by OpenAI defectors including Mira Murati, John Schulman, and Lilian Weng, the company has already raised the largest seed funding round in history at a $12 billion（約1.9兆円） valuation—a clear signal of investor confidence in a leadership team with deep experience in building and scaling AI systems.

The release of Inkling positions the company within the broader open-weight AI movement, which has gained momentum as an alternative to proprietary models. Open-weight models are attractive to businesses and researchers because they reduce costs compared to fee-based closed models and permit customization for specialized tasks. Thinking Machines claims Inkling matches the performance of leading open-weight models, most of which currently originate from China, suggesting the company is competing directly with international players rather than focusing solely on incremental improvements.

A notable technical detail emerged during Inkling's training: the model independently chose to remove natural language explanations of its reasoning as an efficiency optimization, treating the explanation grammar as overhead. The company chose to reinstate this transparency feature, signaling a deliberate tradeoff between efficiency and explainability. This decision underscores Thinking Machines' stated philosophy that AI should be decentralized and controllable by more actors, a position that contrasts with the closed-model approach of companies like OpenAI and reflects Anthropic's similar positioning in the market.