# MercuriusMesh — Cross-Venue Market Microstructure Sandbox (Phase 0) This repository contains a Phase 0 implementation of MercuriusMesh: a deterministic, offline-first sandbox for cross-venue market microstructure experiments. What is included - Core pydantic contracts: LocalBook, OrderEvent, QuoteSnapshot, SharedSignals, PlanDelta - A tiny deterministic two-venue simulator and toy adapters - Deterministic latency, packet-loss, and partition handling for offline-first replay - Tests validating model serialization, delayed delivery, and replay reconciliation Run tests and build 1. Install dev deps: `pip install -r requirements.txt` or `pip install pydantic pytest build` 2. Run `bash test.sh` which runs `pytest` and `python3 -m build` This is a focused chunk (Phase 0). Future work: ADMM-lite coordinator, delta-sync, governance logs, conformance harness and adapters marketplace.