---
phase: 02-model-discovery
plan: 03
subsystem: api
tags: [caching, unified-api, model-discovery, providers]

# Dependency graph
requires:
  - phase: 02-01
    provides: Replicate provider implementation
  - phase: 02-02
    provides: fal.ai provider implementation
provides:
  - In-memory model caching with TTL
  - Unified /api/models endpoint for all providers
  - Multi-provider helper functions (listAllModels, searchAllModels)
  - Cache utilities (getCachedModels, setCachedModels, invalidateCache)
affects: [model-browser, generate-node, phase-3]

# Tech tracking
tech-stack:
  added: []
  patterns: [in-memory caching with TTL, unified API aggregation, partial failure handling]

key-files:
  created:
    - src/lib/providers/cache.ts
    - src/app/api/models/route.ts
  modified:
    - src/lib/providers/index.ts

key-decisions:
  - "10-minute default cache TTL (configurable per call)"
  - "Cache key format: {provider}:models or {provider}:search:{query}"
  - "Unified API uses header-based auth (X-Replicate-Key, X-Fal-Key)"
  - "fal.ai always included in unified response (works without key)"
  - "Partial failures return successful providers with errors array"

patterns-established:
  - "Cache utilities exported from @/lib/providers for reuse"
  - "Unified API endpoint pattern at /api/models"
  - "Multi-provider aggregation with Promise.allSettled"

issues-created: []

# Metrics
duration: 5min
completed: 2026-01-09
---

# Phase 02-03: Model Caching and Unified API Summary

**In-memory caching layer and unified /api/models endpoint aggregating Replicate and fal.ai models**

## Performance

- **Duration:** 5 min
- **Started:** 2026-01-09
- **Completed:** 2026-01-09
- **Tasks:** 3
- **Files created:** 2
- **Files modified:** 1

## Accomplishments

- Created in-memory cache utility with 10-minute TTL for model lists
- Built unified /api/models endpoint aggregating all configured providers
- Added cache utilities export from provider index
- Implemented listAllModels and searchAllModels helper functions
- Partial failure handling - returns models from successful providers with errors array

## Task Commits

Each task was committed atomically:

1. **Task 1: Create model caching utility** - `83ef0b4` (feat)
2. **Task 2: Create unified models API endpoint** - `421620c` (feat)
3. **Task 3: Add provider module exports** - `91a5449` (feat)

## Files Created/Modified

- `src/lib/providers/cache.ts` - In-memory cache with get/set/invalidate and TTL support
- `src/app/api/models/route.ts` - Unified API aggregating Replicate and fal.ai models
- `src/lib/providers/index.ts` - Added cache exports and multi-provider helper functions

## API Reference

### GET /api/models

**Query Parameters:**
- `provider`: Optional, filter to "replicate" or "fal"
- `search`: Optional, search query
- `refresh`: Optional, set to "true" to bypass cache

**Headers:**
- `X-Replicate-Key`: Replicate API key
- `X-Fal-Key`: fal.ai API key (optional)

**Response:**
```json
{
  "success": true,
  "models": [...],
  "cached": false,
  "providers": {
    "replicate": { "success": true, "count": 50, "cached": false },
    "fal": { "success": true, "count": 100, "cached": true }
  },
  "errors": []
}
```

## Decisions Made

- Cache uses simple in-memory Map (no LRU, no persistence)
- Default TTL is 10 minutes - balance between freshness and API quota
- Cache key includes search query for separate caching of search results
- fal.ai always included in unified results (works without API key)
- Unified API returns sorted models (by provider, then name)

## Deviations from Plan

None - plan executed exactly as written.

## Issues Encountered

None.

## Phase 2 Complete

This plan completes Phase 2: Model Discovery. All three plans are now done:

1. **02-01**: Replicate provider with model fetching
2. **02-02**: fal.ai provider with model fetching
3. **02-03**: Model caching and unified API

The model discovery infrastructure is ready for Phase 3: Generate Node Refactor.

---
*Phase: 02-model-discovery*
*Completed: 2026-01-09*