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AI Provider Abstraction Layer

Date: 2025-11-10 Version: 1.0 Author: Software Architect Status: Approved for Development

Overview

The AI Provider Abstraction Layer enables flexible AI provider switching, cost optimization through fallback strategies, and seamless development experiences with local models. This design supports OpenAI GPT-5 → GPT-4.1 fallback for production and Ollama for local development without changing application code. Key Benefits:
  1. Provider flexibility: Swap AI providers without code changes
  2. Cost optimization: Automatic fallback to cheaper models
  3. Development experience: Local Ollama testing (no API costs)
  4. Future-proof: Easy to add Anthropic, Gemini, or custom models
  5. Resilience: Graceful degradation when providers fail

Architecture

Interface Design


Implementation: OpenAI Provider

GPT-5 with GPT-4.1 Fallback


Implementation: Ollama Provider

Local Development with Llama 3.3


Factory Pattern

Provider Selection


Environment Configuration

Development (.env.development)

Staging (.env.staging)

Production (.env.production)


Usage Examples

API Route: Generate Prompts

iOS Client Usage


Prompt Engineering

Journal Prompt Generation

Prompt Template:

Emotion Detection

Prompt Template:

Error Handling

Graceful Degradation

Retry Logic


Testing

Unit Tests (Vitest)

Integration Tests


Performance Optimization

Caching Strategy

Request Deduplication


Cost Optimization

Token Usage Monitoring

Budget Alerts


Future Enhancements

Support for Additional Providers

A/B Testing Different Prompts


  • System Design: /docs/architecture/system-design.md
  • Tech Stack: /docs/architecture/tech-stack.md
  • Async Processing: /docs/architecture/async-processing.md
  • API Contracts: /docs/architecture/api-contracts/ai.yaml
  • Development Setup: /docs/architecture/development-setup.md

END OF AI ABSTRACTION LAYER DOCUMENTATION