DeepSeek open-sources DSec: elastic sandbox infrastructure for agentic training

DeepSeek published a paper on DSec, their internal sandbox system for training agents at scale. The idea is to let models practice with real tools in isolated environments that scale elastically. It handles 100K concurrent sandboxes, 11-second startup latency, and roughly $3 per sandbox. The post doesn't mention a code repo—only the arXiv paper is available so far.