itechmeat/open-second-brain

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# Open Second Brain

![Open Second Brain - your knowledge, amplified by AI](docs/images/readme-poster.jpg)

> An [Obsidian](https://obsidian.md)-native memory layer for your AI agent. Plain Markdown you own, in the same vault you already use.

Open Second Brain plugs into [Hermes Agent](https://github.com/NousResearch/hermes-agent) and turns your Obsidian vault into a memory layer the agent reads and writes through deterministic CLI / MCP tools. Preferences, signals, evidence, and audit trails are real `.md` files under `Brain/` in the vault you already open in Obsidian every day. You can grep them, version them with git, search them in Obsidian, edit them by hand. No daemon, no vector black box, no hidden state outside the vault.

## Why

- **Lives in your Obsidian vault.** Open `Brain/preferences/pref-no-internal-abbrev.md` in Obsidian and you literally see what your agent learned about you - title, status, evidence count, confidence band, body text. Wikilinks, backlinks, graph view all work.
- **You own the data.** Plain Markdown on your filesystem. No service to cancel, no cloud account, no schema migration when a vendor pivots. Syncthing to your other machines if you want.
- **Memory that learns deterministically.** A `dream` pass turns repeat signals into rules and retires the ones nothing applies any more. Counters and atomic file moves - no LLM inside the algorithm, no surprise hallucinations in your memory.
- **One vault, every agent.** Hermes Agent is the primary integration. Claude Code, OpenAI Codex, Cursor, Aider, OpenClaw, opencode, Grok Build, kiro, Copilot CLI, Gemini CLI, and Pi all plug into the same Brain through MCP.

## One vault, many runtimes

```mermaid
flowchart LR
    Vault[("Your vault<br/>Brain/ - plain Markdown")]

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