The Playbook is your single source of truth. It starts as a charter and evolves through every canon. Every experiment result, every decision, every risk gets captured here.
What are you trying to achieve? Be specific about the business outcome, not the technology.
Budget, timeline, regulatory requirements, technical limitations, team capacity.
What is explicitly out of scope? Define the edges so the team does not drift.
What do you not know yet? These become inputs to the Witness and Interrogate phases.