Libraries

Library	Responsibility	Documentation
Data	Acquire, validate, store, and query observations	Data docs
Engineer	Produce features, labels, and research datasets	Engineer docs
Models	Train, select, persist, and run predictive models	Models docs
Diagnostic	Validate data, signals, splits, models, and results	Diagnostic docs
Specs	Define runtime-neutral lifecycle and trading contracts	Specs docs
Backtest	Simulate lifecycle, execution, risk, and accounting	Backtest docs
Live	Run shared contracts against paper and live adapters	Live docs

This order describes a common user workflow. It does not assert a direct package dependency between every adjacent library. ml4t-specs owns shared contracts used by simulation and live execution.