Replace the previously selected Claude Haiku with Google Gemma 4 for AI features like post text summarization, connection suggestions, content categorization, tagging, and search enhancement, due to better performance and cost efficiency.
## Context ADR 015 selected Claude Haiku for AI features (title auto-generation, etc.), but no AI features have been implemented yet. Google Gemma 4 (released 2026-04-02, Apache 2.0) offers equivalent or better performance at 1/5 the cost. Since we're starting fresh, use Gemma 4 from the beginning — no migration needed. ## Use Cases in Gleisner - Post text summarization (title auto-generation) - Connection suggestion between posts - Content categorization / tagging - Search enhancement - Future: creative assistant features These are lightweight NLP tasks — E4B (4.5B params) should suffice. ## Why Gemma 4 over Claude Haiku | | Claude Haiku | Gemma 4 API | |--|-------------|-------------| | Cost | $0.25/M in, $1.25/M out | ~$0.04-0.08/M tokens | | License | Proprietary | Apache 2.0 | | Self-host option | No | Yes (GPU or on-device) | | Performance | Good for lightweight tasks | Comparable or better | | Vendor lock-in | Anthropic dependency | Open model, multiple providers | ## Pha