GBrain
lastmod 2026-04-10created 2026-04-101 edits
An open-source personal knowledge base tool that unifies scattered Markdown files on top of Postgres and provides semantic hybrid search.
About
- A personal knowledge management (Knowledge Brain) tool built by YC CEO Garry Tan in Karpathy's LLMWiki style
- Can also be used as a CLI/library, but using it integrated with OpenClaw is recommended
- Unifies scattered Markdown files into a Postgres-based knowledge base and provides semantic hybrid search
- Combines vector (pgvector HNSW) + keyword (tsvector) with RRF (Reciprocal Rank Fusion)
- Automatically generates 2 alternative phrasings of the query with Claude Haiku (multi-query expansion); includes a 4-stage deduplication pipeline covering vector/keyword search and more
- A distinctive knowledge model that separates each page into compiled truth (current best understanding, fully rewritten on new evidence) and timeline (append-only evidence tracking)
- Provides an MCP server with 20 tools — integrates directly with AI agents such as Claude Code and Cursor
- 7 AI agent skills built in
- 3-tier chunking strategy: Recursive/Semantic/LLM-guided
- v0.2.0 added git-based incremental sync and Supabase Storage file management
- MIT license / TypeScript
See also
- PostgreSQL
- pgvector
- Claude
- MCP
- Obsidian
- Notion
- Logseq
- Roam
- Supabase
- TypeScript
- LLMWiki
- Wiki
- gstack