Trinity-Large-Thinking by Arcee

Trinity‑Large‑Thinking is an open‑weight language model designed for complex, long‑horizon reasoning and multi‑turn tool calling. It targets developers and researchers building agentic AI systems that require sustained context and sophisticated decision making. The model is released under the Apache 2.0 license and is available through the Arcee API and OpenRouter, allowing integration into custom applications.

The project emphasizes cost‑efficient scaling, claiming performance comparable to the proprietary Opus 4.6 model while operating at roughly four percent of the price. Its architecture supports online reinforcement learning, enabling continuous improvement after deployment without needing to replace the model. This approach aims to keep operational expenses low for large‑scale deployments.

Arcee AI provides documentation for pairing Trinity‑Large‑Thinking with the Hermes Agent, covering installation, tool configuration, and launch steps. The initiative also includes the Trinity Builders Program, offering free inference credits to developers, researchers, and open‑source contributors who work with the model.