Compare GPT-5.1 Instant vs. Inkling

GPT-5.1 Instant is an advanced AI model tailored for everyday users, merging rapid response times with enhanced conversational warmth. Its adaptive reasoning capability allows it to determine the necessary computational effort for tasks, ensuring swift responses while maintaining a deep level of understanding. By focusing on improved instruction adherence, users can provide detailed guidance and anticipate reliable execution. Additionally, the model features expanded personality controls, allowing the chat tone to be adjusted to Default, Friendly, Professional, Candid, Quirky, or Efficient, alongside ongoing trials of more nuanced voice modulation. The primary aim is to create interactions that feel more organic and less mechanical, all while ensuring robust intelligence in writing, coding, analysis, and reasoning tasks. Furthermore, GPT-5.1 Instant intelligently manages user requests through the main interface, deciding whether to employ this version or the more complex “Thinking” model based on the context of the query. Ultimately, this innovative approach enhances user experience by making interactions more engaging and tailored to individual preferences.

Inkling is Thinking Machines’ open-weights foundation model built for customization, multimodal reasoning, and agentic AI workflows. The model uses a Mixture-of-Experts architecture with 975 billion total parameters and 41 billion active parameters, making it large in capacity while activating only a subset of experts per token. Inkling supports up to a 1 million token context window and was pretrained on 45 trillion tokens spanning text, images, audio, and video. It is designed as a broad generalist model with strengths across coding, reasoning, instruction following, factuality, tool use, vision, audio understanding, forecasting, and safety. Developers can tune its thinking effort to trade off latency, cost, and performance, which is useful for production systems that need efficient reasoning at scale. Inkling can be fine-tuned on Tinker, tested in the Inkling Playground, and deployed through partners such as TogetherAI, Fireworks, Modal, Databricks, Baseten, vLLM, SGLang, llama.cpp, and Hugging Face transformers. The model can generate applications, operate tools, create styled artifacts, reason over visual and audio inputs, and support long refinement loops for collaborative work. Thinking Machines also previewed Inkling-Small, a lighter Mixture-of-Experts model with 276 billion total parameters and 12 billion active parameters for lower-cost and lower-latency workloads. By combining open weights, multimodal training, agentic capabilities, efficient reasoning, and fine-tuning support, Inkling gives builders a flexible AI foundation for specialized products and workflows.