Claude Code turned 4,700 Obsidian notes into a working neural network in one evening.Not a metaphor. An actual net. 17 inputs. 26 neurons in the hidden layer. ReLU activation. Every input node is a folder from his vault.The setup took 3 prompts.Prompt 1: Claude Code reads the vault. 4,700 markdown files, 6 years of notes, 2.1M words. It builds embeddings for every note and maps the link graph.Prompt 2: it writes the network from scratch. No PyTorch. No TensorFlow. Raw JavaScript, 900 lines, runn