Purpose Structure the first 90 days of a VP or CPO transition as a diagnostic process, not an execution sprint. The single most common failure in senior product leadership transitions is acting before understanding — changing structures, replacing people, or announcing strategy before building the evidence base that makes those decisions defensible. This playbook runs in three phases: Diagnose (Month 1), Validate (Month 2), Act with Evidence (Month 3). Each phase builds on the last. Skipping phases doesn't accelerate results — it guarantees expensive reversals. This is not a 100-day plan for…