Claudian integrates AI coding assistants directly into the Obsidian note-taking app, turning the vault into a working directory for agents like Claude Code and Codex. It provides a chat sidebar for conversational interaction, inline editing with word-level diff previews, slash commands and reusable skills, @mention support for vault files and MCP servers, plan mode for approved implementations, and multi-tab conversation management. The plugin connects to AI providers via their respective CLIs and supports the Model Context Protocol for extending agent capabilities.