Fireship: 7 New Open-Source AI Tools — Prompt Fu (Prompt Unit Testing) and Open Viking (Tiered Agent Memory) Are Builder Standouts

Fireship (YouTube)·medium signal

Fireship's latest roundup (624K views) covers 7 new open-source tools; two are highest-signal for builders: Prompt Fu (unit testing framework for prompts — tests across multiple models with automated red-team and injection checks) and Open Viking (file-system-based context/memory database for agents with tiered loading and automatic compression to reduce token costs). Other tools include The Agency (Claude Code startup role templates), Impeccable (design CLI with 17 commands to de-genericize AI-generated UIs), and Nano Chat (full LLM pipeline for ~$100 GPU cost).