HELIX: Model-Harness Co-evolution for Recursive Self-Improvement

HKUDS (Tianyu Fan, Chao Huang) closes the loop between the two things that make an agent: build harnesses for a fixed model, update the model from verified sibling trajectories, rebuild the harnesses as the model changes. HELIX is the substrate that makes this tractable — agent systems decompose into typed ports, reusable atoms, recipes, product shells and runtime policies, so every harness intervention is explicit, auditable and source-traceable.

Completes HKUDS's harness cluster (OpenHarness, nanobot, CLI-Anything) with the co-evolution step; MIT-licensed, released August 17, 2026 (early: ~30 stars at filing).