Obsidian Second Brain

This project is an open source skill that gives AI coding agents persistent memory stored as plain markdown in an Obsidian vault. It is built primarily for Claude Code and is also packaged for Codex, Gemini CLI, OpenCode, Hermes, Pi, Grok Bot and Antigravity. Because the memory lives in ordinary notes, the vault stays readable and editable by the user as well as the agent. The skill provides roughly 45 commands for saving decisions, people and tasks, ingesting sources, finding information, and running daily notes and reviews. It includes hybrid semantic search and a vault that updates existing pages when new sources arrive rather than only appending. Research commands cover X, the web, YouTube and podcasts. Optional scheduled agents run morning, nightly, weekly and health routines to maintain the vault, and the background agent is off by default. A maintenance rule called OKM requires each stored fact to be timeless, dated, or a pointer to its source. Installation is through the Claude Code plugin marketplace: add the repository, install the plugin, set the OBSIDIAN_VAULT_PATH variable in the Claude Code settings file, restart, and run the init command. A classic route clones the repository into the Claude skills folder and runs the included install and setup scripts, and a build script produces packages for the other supported platforms. It requires a supported agent CLI, git and uv. Ollama for local semantic search and Whisper for audio are optional. The project is released under the MIT license and is free. Core vault commands need no API keys, while some research commands use keys for services such as xAI, Perplexity, Gemini, YouTube or OpenAI, with free source fallbacks for the basic research commands. The README links to the author's newsletter and blog.