**Core Problem:** Users need a frictionless way to log daily actions and track their impact without overwhelming complexity.  

**Invariants for Success:**  
1. Users can log actions in under 10 seconds.  
2. The feed clearly shows the relationship between actions and outcomes.  
3. The default view prioritizes today's activities.  
4. Reflection is optional and unobtrusive.  

**Must-Have Outcome of the MVP:** A single screen that allows users to log actions quickly, view a feed of their logs, and see metrics associated with those actions.  

**Risky Assumptions Worth Testing:**  
1. Users will find value in logging actions daily without needing prompts or templates.  
2. The auto-attachment of metrics will be effective and accurate enough to encourage continued use.  
3. Users will prefer a minimalist design over more detailed analytics or features.  

**Leanest Path to Value:**  
Create a single screen with:  
- A quick log section (step chips and text field).  
- A compact evidence feed showing logged actions grouped by date.  
- A simple empty state with examples to encourage first-time use.  
- Keyboard shortcuts for fast logging.  
This setup allows users to log actions and see immediate feedback, fulfilling the core problem while minimizing complexity.