oh-my-second-brain

A constellation of knowledge, still yours. A user-owned knowledge and convention layer for Obsidian, Markdown, and AI agents.

Quick start · How it works · Documentation · Releases · 한국어

Your vault already holds ideas, decisions, and things you learned. OMS helps your agents find that knowledge and write within the conventions you defined. No new note format. No prescribed folder system. No handover of your knowledge to a single host.

Obsidian stays the command center. Your notes stay plain Markdown, readable and editable even when OMS is not running. Connect Claude Code, Codex, or Hermes to the same vault through their host integrations.

Why OMS?

Recall what you already know Search your existing notes with lexical retrieval. Choose vector, HyDE, query expansion, or reranking explicitly when you need them.

Your vault, your vocabulary Define the meaning of folders and properties. OMS records your conventions instead of shipping a system you have to adopt.

Give agents a shared contract Seal your vault conventions through setup. Supported write paths check the whole note against that contract before saving it.

Keep the files you own Keep using your Markdown notes and templates. Setup does not rewrite them, and the sealed contract lives outside the vault.

Connect across hosts Use native integrations for Claude Code, Codex, and Hermes, with four MCP tools and six shared workflow skills.