# Research Findings for CLI App with MFA Support

## Phase 0: Outline & Research

### Decision
Selected Click as the CLI framework for the Python application based on the project constitution's requirement for CLI interfaces (must be Click or Typer). Decided to create a new CLI module that interfaces with the existing API structure.

### Rationale
- The constitution specifically requires either Click or Typer for CLI interfaces
- Click provides excellent support for multi-level commands which is needed for auth/sync/status operations
- Click has good support for handling MFA flows through prompts
- Consistent with the existing backend architecture of the project

### Technology Choices Made
- **CLI Framework**: Click (as required by constitution)
- **API Client**: httpx (modern, async-capable, excellent for API interactions)
- **Configuration**: YAML (as required by constitution)
- **Output Formats**: JSON, table, CSV (as required by constitution)
- **Token Storage**: Local JSON file with appropriate security measures
- **Authentication Flow**: OAuth2/MFA integration with existing backend API

### Alternatives Considered
- **Typer vs Click**: Typer offers better type hints integration, but Click was selected to match constitution requirements
- **argparse**: Simpler but lacks the advanced features needed for this CLI application
- **Direct HTTP requests**: httpx was chosen over basic requests library for better async support and API interactions

### Integration Approach
The CLI app will integrate with the existing backend API, reusing authentication mechanisms and sync endpoints. This approach leverages existing functionality while providing a new interface for users who prefer command-line operations.

### Security Considerations
- Local token storage will use appropriate file permissions (600)
- MFA handling will follow platform-appropriate secure input methods
- Token refresh mechanisms will be implemented to handle expiration