Agents need hands — a personal second brain with n8n as its deterministic kernel

Agents can think - but they cannot act. Over the past months I built a personal "Second Brain" spanning 25 years of my life: 9,397 scanned documents, 3,289 notes, the ERP of my antique watch business, and two fully transcribed YouTube channels - 37,554 searchable memories, visualized as a 3D galaxy and answered by local models only. Zero cloud, zero API fees. n8n is the deterministic kernel of this system: an MCP Server Trigger turns eight workflows into tools any agent can call, a Switch-based router cascade decides where each question goes (66/68 reproducible routing accuracy, no LLM in the hot path), and the execution log caught every lie my agent ever told me. This talk shows the real workflow graphs, the traps that cost me nights - nondeterministic vector search, stemming floods, invented facts - and why building this convinced me that n8n matters MORE in the agent era, not less. With a live demo: the galaxy flies itself, and Telegram answers from my pocket.