**Architecture**

MercuriusMesh (Phase 0) — a deterministic, offline-first sandbox for cross-venue experiments.

Tech stack
- Language: Python 3.9+
- Runtime packages: pydantic (data contracts), pytest (tests)

Project layout
- mercuriusmesh/: core package with contracts, toy adapters, and a deterministic simulator with latency and partition support
- tests/: pytest test-suite
- test.sh: runs tests and builds the package

Guiding principles
- Keep core contracts minimal and canonical: LocalBook, OrderEvent, QuoteSnapshot, SharedSignals, PlanDelta
- Deterministic replay: append-only event log; replay reinitialises adapters, replays events, and preserves queued/offline order delivery
- Small, well-tested chunks: this agent implements Phase 0 core contracts + toy two-venue demo

Testing
- Run `bash test.sh` to run the full verification: pytest and `python3 -m build`.

Contribution rules
- Follow the existing contracts module when adding fields; prefer additive, backward-compatible changes
- Add adapter conformance tests to `tests/` and update AGENTS.md when adding new adapters