GBrain: Garry Tan’s Open‑Source AI Memory Engine

Overview

GBrain is an MIT‑licensed, self‑hostable memory layer for AI agents, created by Garry Tan, President and CEO of Y Combinator. It stores explicit facts with provenance, supports corrections and withdrawals, and shares the same memory across multiple agents.

Key Features

• Explicit, source‑backed facts – every claim is linked to a source page.
• Correction & withdrawal – facts can be updated or removed.
• Cross‑agent sharing – a single brain can be used by many agents.
• Keyword & semantic retrieval – fast keyword search plus vector‑based semantic search.
• Synthesis layer – generates a concise answer with citations and a gap analysis.
• Typed knowledge graph – supports graph traversal for relationship queries.
• Hosted option – gbrain.io offers a paid, managed hosting service.
• Local deployment – install with Bun (≥ 1.4.4) and run 24/7 for continuous ingestion.

How It Works

1. Setup – run `gbrain setup` to configure the brain and connect it to your chosen AI harness (Claude, Codex, ChatGPT, etc.).
2. Ingestion – ingest meetings, emails, tweets, voice calls, and other documents. The brain enriches and consolidates data overnight.
3. Retrieval – agents query the brain via keyword search (`gbrain search`) or synthesis (`gbrain think`).
4. Enrichment – background jobs deduplicate, fix citations, score salience, and detect contradictions.
5. Sharing – authorized users can publish skills and share the brain with teams.

Practical Implications

• Personal agents: keep a persistent memory of your interactions and knowledge, improving over time.
• Team brains: create a shared institutional memory that respects source and operation grants.
• Verification: the brain’s gap analysis tells you what it doesn’t know, guiding follow‑up questions.

Getting Started

```bash

Install via Bun

bun install -g github:garrytan/gbrain#stable

Initialize a keyless brain

gbrain setup

Expose over Tailscale for remote use

gbrain mcp expose ```

Verification

• Check the brain’s readiness with `gbrain search --ready`.
• Inspect source pages with `gbrain sources inspect`.
• Use the hosted service at gbrain.io for a zero‑install experience.

Conclusion

GBrain offers a robust, open‑source foundation for building AI agents that remember, reason, and grow. Its explicit memory model and synthesis capabilities make it a powerful tool for both individuals and teams.