# Eight open-source "second brain" repos for AI agents, including Garry Tan's gbrain

> Original title: This is f*cking insane, the CEO of Y Combinator open-sourced his own second brain and most people still don’t know it exists

- Source: X search: AI open-source releases
- Published: 2026-11-08T14:14:24.000Z
- Bad Influence: https://badinfluence.news/items/jgbahwpufhy3qyi80rmx15zdi
- Original: https://x.com/imryven/status/2119433356584604119

## Summary

A viral X post lists eight open-source "second brain" repositories for AI agents and personal knowledge management, including gbrain by Garry Tan, which keeps a source for every fact and shares one memory across agents. Other entries include Andrej Karpathy's LLM wiki idea file, ai-memory for handing work between Claude Code and Codex in plain markdown, and baalda, a team markdown memory that people and agents edit together.

## Post

This is f*cking insane, the CEO of Y Combinator open-sourced his own second brain and most people still don’t know it exists

8 second brain repos you haven’t seen yet:

-> gbrain (by garrytan)
http://github.com/garrytan/gbrain
the second brain of the YC CEO, every fact keeps its source and every agent shares one memory

-> llm wiki (by karpathy)
http://gist.github.com/karpathy/442a6bf555914893e9891c11519de94f
the original idea file behind all of this

-> ai-memory (by akitaonrails)
http://github.com/akitaonrails/ai-memory
hand the work from Claude Code to Codex without losing context, memory lives in plain markdown

-> agent second brain (by smixs)
http://github.com/smixs/agent-second-brain
send a voice note in Telegram and it lands as a linked note in your Obsidian vault

-> cog second brain (by huytieu)
http://github.com/huytieu/COG-second-brain
33 skills and 10 agents running on plain markdown, no database

-> open second brain (by itechmeat)
http://github.com/itechmeat/open-second-brain
a nightly pass turns the corrections you keep repeating into rules your agent follows

-> claude second brain (by jessepinkman9900)
http://github.com/jessepinkman9900/claude-second-brain
one npx command scaffolds Obsidian, Claude Code and local search

-> baalda (by naveedharri)
http://github.com/naveedharri/baalda
a team second brain where people and agents edit the same markdown files

the CEO of Y Combinator runs his agents on this
you are still digging through bookmarks

[Video](https://badinfluence.news/api/img-proxy?u=https%3A%2F%2Fpbs.twimg.com%2Famplify_video_thumb%2F2119431899001057280%2Fimg%2FKyxO1N_THTHAVl_O.jpg&mode=thumb&exp=1794528000&sig=ef389c55aad80e1b)

## Quoted post @imryven

> https://x.com/i/article/2115042274614599680

https://x.com/imryven/status/2115046979659055476