The problem
Most AI feels like it forgets you the second you close the tab.
Out-of-the-box LLMs are stateless. They re-meet you every session, lose context across days, and can't track the entities, relationships, and history that make your judgment yours. For someone like Garry Tan — running an accelerator, talking to hundreds of founders — that's a non-starter.
What he built
A graph, a toolbelt, and a nightly loop.
GBrain is three layers stacked on top of an off-the-shelf model. The model didn't get smarter — the context around it did.
GBrain stack
Layer 01 · Knowledge
Graph + entities
A knowledge graph of people, companies, and relationships, captured from notes, conversations, and reading. Persistent across sessions. The AI knows what you know.
↓
Layer 02 · Tools
MCP tools (74)
A library of tools the AI can call: graph search, entity sweeps, citation lookups, file reads. Each tool is a thin wrapper around a real function. Composable, observable.
↓
Layer 03 · Loop
Nightly dream cycle
66 cron jobs run between you and the next morning: memory consolidation, citation fixing, entity sweeps, dedup. The AI wakes up cleaner than it went to sleep.
The result
An AI that gets sharper overnight.
GBrain runs 24/7. The knowledge graph compounds. Citations get fixed. Entities get merged. By morning, the AI knows more — and more accurately — than it did yesterday. And because it's open source, you can run the same thing.
Garry also published gstack — his 23-tool Claude Code configuration. Same posture: keep the model fixed, sharpen the context and tools around it.
The model can do most of what I need. The hard part is giving it the context, the memory, and the tools to actually do it.
— Garry Tan, President & CEO, Y Combinator
Sources
GBrain (github.com/garrytan/gbrain)
gstack (github.com/garrytan/gstack)