# Smart Second Brain plugin for Obsidian Smart Second Brain (plugin id `smart-second-brain`) is a local-first knowledge companion for Obsidian. Version 2 (2026) turned it from the chat-only assistant of v1 into three tools: search, a topic graph and AI agents. It works on desktop and mobile. ## Features (v2) - **Search**: full-text search that also indexes **PDF content**, with no AI needed. Press `Tab` to rerun the same query semantically (requires an embedding model). Typing `#` or `/` turns into tag and folder filter chips. A search without results can be sent to the agent, or turned into a new note - **Smart Graph**: automatic topic regions (with a granularity slider and an "Immerse" mode). It highlights bridge notes and orphans, and draws semantic links between notes that don't link to each other - **Agents**: chat with your notes using [[Large Language Models (LLMs)]] (local through [[Ollama]], or OpenAI, Anthropic and others). Answers cite notes as wikilinks, and proposed edits are staged as inline diffs you accept or reject Search and the graph work right after installation, without any AI provider. Add an embedding model for semantic search and topics, and an AI provider for the agents. ## Version 1 v1 (2024-2025) was a chat interface: an assistant that read your notes through RAG, could run fully offline with Ollama, and kept your data private. Older articles and videos describe that version. ## Good to know - It does a lot: search, graph and agents compete for attention. Use the parts you need - It checks for updates daily by fetching its manifest from GitHub (can be disabled) - About 70,000 downloads; v2.3.0 was released on 2026-09-28 (actively maintained as of 2026-10) ## References - Source code: https://github.com/s2b-dev/smart-second-brain (formerly https://github.com/your-papa/obsidian-Smart2Brain) - Documentation: https://smartsecondbrain.dev - https://community.obsidian.md/plugins/smart-second-brain ## Related - [[Obsidian AI Plugins]] - [[Smart Connections plugin for Obsidian]] - [[Omnisearch plugin for Obsidian]] - [[Ollama]]