The clearest AI foundations explainer I've found — neural networks through agents, no PhD required. I come back to this when I need to level-set with engineers still building their mental model of how these systems actually work.
The harness around the model matters more than the model itself. Cole Medin builds Anthropic's full playbook hands-on — CLAUDE.md hierarchy, self-improving hooks, path-scoped skills, subagents for exploration — and the self-improving stop hook alone changes how you think about keeping the AI layer from rotting over time.
Anthropic's official plugin directory — the right starting point before going anywhere else. First thing I did after reading it was check what equivalent exists inside Amazon's internal tooling.