Hexo Labs Open-Sources SIA: A Self-Improving Agent That Updates Both the Harness and the Model Weights
Most AI agents stop improving once a human stops tuning them. The model is fixed. The scaffold around it is fixed. Hexo Labs wants to move both at once. It released SIA (Self-Improving AI) this week as an open-source framework under an MIT license. The core claim of this research is narrow but concrete. SIA edits both the agent’s scaffold and the model’s weights inside one self-improving loop. What is SIA (Self-Improving AI) SIA splits a task-specific agent into two parts. The first is the harness, also called the scaffold. That covers the system prompt, tool-dispatch logic, retry policy, and answer-extraction code. The second part is the model weights themselves. Three LLM components drive the loop. A Meta-Agent writes the initial scaffold from a task specification and any reference code. A Task-Specific Agent runs the task and logs every step. A Feedback-Agent then reads that full trajectory and decides what to change. That decision is the key idea. A...
