tl;dr: Echo is a routing system that dynamically allocates queries across a pool of open-weight models (GLM-5.2, Kimi K2.7, etc.), deciding per-request which models participate and how their outputs combine. The author claims it outperforms any single model in the pool and matches Fable's aggregate performance at roughly one-third the inference cost. A chat UI and OpenAI-compatible API are available for testing, with coding/agentic task evaluation still underway.