LongCat-2.0 vs. Kimi K3

LongCat-2.0 signifies a remarkable leap forward in the field of language models, boasting an impressive 1.6 trillion parameters through a Mixture-of-Experts architecture that utilizes AI ASIC superpods, with around 48 billion parameters activated per token, demonstrating outstanding proficiency in coding and agentic functions. This model notably surpasses its predecessors by incorporating a large-scale sparse architecture along with specialized post-training techniques designed specifically for applications in real-world software development, tool usage, long-context reasoning, and intricate agent operations. Entirely built and executed on AI ASIC superpods, LongCat-2.0's pretraining involved processing over 35 trillion tokens and countless accelerator hours, highlighting the forefront of training techniques on state-of-the-art hardware. To further enhance its capabilities on tasks that require long-term contextual awareness, the model integrates LongCat Sparse Attention and is trained with hundreds of billions of tokens derived from 1M-context datasets, which empowers it to adeptly handle ultra-long context challenges and maintain a comprehensive understanding of extensive documents. This unique blend of features not only establishes LongCat-2.0 as an innovative leader in advanced language models but also sets a new benchmark for future developments in the domain. Its capabilities are likely to inspire a new wave of research and applications in the field.

Kimi K3 is Moonshot AI’s most advanced model, designed for high-end reasoning, software engineering, multimodal understanding, knowledge work, and agentic AI applications. The model has 2.8 trillion parameters and is built on Kimi Delta Attention, a hybrid linear attention mechanism created for long-context performance. It also uses Attention Residuals and supports a native context window of up to 1 million tokens. This makes Kimi K3 suitable for tasks involving large codebases, long research materials, enterprise documentation, multi-file analysis, legal documents, technical manuals, and complex workflows. Kimi K3 always has thinking mode enabled, with reasoning effort configured through the reasoning_effort field and maximum effort currently supported as the default. Developers can use the model through an OpenAI-compatible API, making it easier to integrate with existing SDKs, clients, and application infrastructure. The model supports streaming responses with separate reasoning and final-answer deltas, allowing applications to display reasoning progress and final content differently. Kimi K3 also supports strict structured output with JSON Schema, partial mode for continuing from a prefix, custom tool calling, required tool use, and dynamic tool loading through system messages. Its vision capabilities support image and video inputs through base64 or uploaded files, enabling analysis of visual content alongside text. Automatic context caching helps workflows that reuse long prefixes, such as large knowledge bases or persistent system context, without requiring developers to manage cache IDs manually. By combining frontier-scale parameters, long-context processing, visual input, structured outputs, tool orchestration, and developer-friendly API compatibility, Kimi K3 gives teams a strong foundation for advanced AI agents, coding assistants, research systems, enterprise automation, and multimodal applications.