Developers can access the open source SemIf decision model for free through LangSmith Gateway for a 7 day period starting September 21. The model is based on Qwen 3.5 and is compatible with the TypeSafe SDK, requiring only a configuration string change for deployment. This update establishes decision models as a primary component of the gateway's infrastructure to expand the available tool ecosystem.

Unlike standard chat models that generate text, decision models provide typed answers such as probabilities or rubric scores that allow software to branch on logic. This architecture removes the need for developers to coax JSON from generative AI and enables automated action based on confidence thresholds. SemIf provides a free alternative to proprietary decision models like Jev for developers integrating these capabilities into their applications.