TL;DR: To fix the scalability problem of single-agent harnesses, this paper introduces Raven, an open-source multi-agent ecosystem that automatically builds and evolves its own harnesses. Title: Raven: The Harness of Harnesses for Composable Agentic Intelligence URL: Points 🧩 Treats each model-harness pair as a unit of composition; a Host Agent decomposes tasks and assigns them to specialist agents as a DAG 🧠 EverOS (memory) and Skill Forge (skill retrieval/reuse) let the system carry past experience across tasks 🔬 Proves a "composition soundness" theorem where error rates simply add up across operations, and shows with an XOR example that composed agents can exceed what any single agent can do 📊 Ranks #1# on all four metrics of the new MAOB benchmark, beating the strongest baseline by +10.4–10.5 points on Exact Match 🛠️ Specialist agents — Raven-Research, -Code, -Design, -Oncall — all consistently beat their baselines too 🔁 A diagnosis-driven harness self-evolution mechanism improves performance across domains even with a frozen model backbone It's compelling to see theory and empirical results both back up why multi-agent composition actually works. #MultiAgent# #AgentHarness#