Hey HN,

  I've been lifting for years and got frustrated with fitness apps that either (a) generate a static plan and forget about you, or (b) require manual logging with no intelligence.
 
  So I built Arvo—an AI personal trainer that adapts after every single set, not just at the start of your workout.
 
  Why 19 agents instead of one? Each handles a specific job:
  - Exercise Architect (selects movements based on equipment/goals)
  - Load Navigator (calculates weight adjustments based on RIR)
  - Volume Manager (tracks MEV/MAV/MRV per muscle group)
  - Pattern Scout (extracts insights from natural language notes)
  - Movement Adapter (biomechanical weight conversion when swapping exercises)
 
  They coordinate to make decisions in <500ms.
 
  Example: You finish set 1 of bench press, felt easy (RIR 4). Arvo bumps weight +2.5kg for set 2. Set 2 was a grind (RIR 1). Arvo keeps the weight but suggests longer rest.