Build an AI Second Brain with Obsidian

The short version

A second brain fails for one of two reasons: you stop feeding it, or you stop trusting it. An AI second brain fixes both. The AI does the tedious part (filing, summarizing, linking), and because everything flows through one vault, the answers it gives you are grounded in your own notes instead of a model's guesses. The stack is deliberately boring: Obsidian for the vault (plain Markdown files you own forever), PARA for structure, git for history, and an LLM connected over MCP so it can read and write your notes like a careful assistant. Structure first. PARA gives you four top-level folders: Projects (things with a deadline), Areas (things with a standard to maintain), Resources (things you might use), Archives (things that are done). Every note lands in exactly one. Add a short inbox folder for raw capture, and empty it on a schedule; capture must be frictionless or it will not happen. Then make the vault canon. One rule changes everything: if it is not in the vault, it does not exist. Meeting notes, decisions, client facts, how-tos: they live as vault pages, not in chat histories or your head. Keep raw material (transcripts, clippings, exports) in a separate raw folder that you treat as source, never as the place you think in. Then connect the AI. An MCP server for Obsidian gives any capable LLM read/write access to your vault. Now "where did we land on pricing?" is answered from your own decision notes, with the page cited. The assistant files inbox captures into PARA, proposes links between related notes, and drafts new pages from raw transcripts, always into the same structure you already navigate. Finally, run loops. A nightly job summarizes what changed and flags notes that contradict each other. A weekly job compiles each active project into a single up-to-date brief. The loops are what keep the vault alive after week two, when manual discipline normally dies. The full guide walks through the vault layout, the MCP setup, the exact loop prompts, and the habits that make it stick. It is inside the PDF.

The short version

From this guide to done