If you're building an OMS or EMS, this walks you through order state machines, FIX protocol flows, and all the edge cases that bite you in production. It covers the full lifecycle from order entry through fills, cancels, and replacements, including the race conditions between cancel requests and executions that cause most bugs. You'll find the canonical state definitions (New, Pending New, Accepted, Partially Filled, and the terminal states), valid transitions, ClOrdID chaining for cancel/replace workflows, and pre-submission validation patterns. The material on CAT audit trails and order persistence for failover is solid. This is the reference you want when debugging why an order hit an impossible state or designing recovery logic.
npx skills add https://github.com/joellewis/finance_skills --skill order-lifecycle