harness-router

harness-router is an open-source Python tool that acts as a decision layer for AI coding agents and agent harnesses. It optimizes tool calling by using normal calls when obvious, a lightweight decision model called Jev for ambiguous choices, and Monte Carlo Tree Search (MCTS) for decisions where multi-step consequences matter. It reduces latency and computational overhead by reserving heavy computation only when necessary. It integrates as an MCP server and supports efficient routing in AI agent workflows.