Laguna S 2.1 is Poolside's 118B total parameter Mixture-of-Experts coding model with 8B activated parameters per token, designed for agentic coding and long-horizon software engineering tasks. It features a sparse MoE architecture with 256 routed experts, mixed sliding-window and global attention, and native interleaved reasoning with an enable_thinking flag. The model supports a context window of up to 1 million tokens and is compact enough to run on a single NVIDIA DGX Spark. Released as open-weight under the OpenMDW-1.1 license, it is available via Hugging Face and multiple inference providers.