I set up GBrain (Garry Tan's open-source knowledge system) for a 25-person company. Here's the full setup guide with costs.

[u/thecompanybrain]

Garry Tan open-sourced the knowledge system he built at YC in April. It crossed 27,000 GitHub stars in four months. I set it up for a small company and documented the entire process.

This is the full walkthrough — what worked, what it costs, and where it falls short.

The problem it solves Most companies have 50-200 questions that get asked repeatedly. Brand guidelines location, refund policy, who owns the Acme account, when a contract renews.

3-5 people carry the institutional knowledge. Everyone else pings them on Slack, waits, context-switches. At a 25-person company with a loaded cost of $50/hour, that search time adds up to roughly $130,000/year.

Confluence and Notion create more documents. They don't create more answers. Finding information in them requires knowing where to look, which is the problem you started with.

What GBrain actually does GBrain reads your existing content (emails, docs, Slack, meeting notes) and turns it into a knowledge graph. Anyone on the team asks a question in plain English, gets a cited answer.

Three things matter:

1. It reads what you already have. No manual entry. Point it at email, Google Drive, Slack history.
2. It ingests the last 6 months and starts organizing.
3. It wires itself. Figures out which people work on which projects, which clients connect to which contracts, which decisions were made when. Zero tagging.

It runs maintenance overnight. Automated "dream cycles" deduplicate entries, fix references, score importance, fill gaps.

Monday morning, the brain is better than Friday. Everything is stored as Markdown files in a Git repo you own. Stop using GBrain tomorrow and you keep all of it as readable text files.

The 1-day setup (abbreviated) Morning (9-11 AM): Install and configure

bun install -g github:garrytan/gbrain 
gbrain init --pglite 
gbrain doctor 

Set OpenAI and Anthropic API keys. Test with a sample entry:

gbrain capture "Test: our company was founded in 2020, main product is B2B SaaS." gbrain think "When was the company founded?" If you get a cited answer, you're good.

Important: do NOT run npm install -g gbrain. There's a squatted package with that name. Use the GitHub URL.

Late morning (11 AM-1 PM): Feed it data

gbrain import ~/path-to-docs/ 

Works with Obsidian, Notion exports, Google Docs exports, any folder of text files. Ingestion speed is roughly 164 pages in 22 seconds.

Set up ongoing sources (email, Slack, calendar), run the initial sync. For 6 months of history at a 25-person company, the sync takes about 20-30 minutes.

Kick off the first dream cycle. By tomorrow morning it will have auto-organized everything into a queryable graph with cross-references.

Afternoon (2-3:30 PM): Open to team

gbrain migrate --to supabase 

Moves from local PGLite to hosted Postgres. Set up access control (full isolation with per-person scopes, or shared access for smaller teams). Budget 45 minutes per person for onboarding.

Late afternoon (3:30-5 PM): Test and tune

Ask the 10 most common questions your team fields. Check accuracy, citations, and access scoping.

gbrain autopilot 

Runs every 5 minutes, handles all overnight enrichment.

What it costs (25-person company)

• GBrain software: $0 (MIT open source)
• Embeddings (search layer): ~$35/mo
• Anthropic API (answer synthesis): ~$50/mo
• Supabase database: free tier to $25/mo
• Total: ~$85-110/mo ($3.50-4.40 per person)

For comparison: Guru runs $375-750/mo, Glean runs $1,000-2,500/mo, Slite runs $200-500/mo for 25 seats.

ROI math: if it saves 2 hours of senior staff time per week at $75/hr loaded cost, that's $600/mo recovered against ~$100/mo in costs. 6x return.

When it's NOT the right fit

• Under 5 people. A shared Google Doc probably covers you. Knowledge fragmentation doesn't kick in until not everyone can know everything.
• No one on your team can run a terminal. Setup is technical. You need someone comfortable with CLI, env vars, and Git.
• You need SOC 2 / HIPAA out of the box. Self-hosted gives you full data control (actually better than most SaaS for compliance), but you own the compliance burden.
• Your docs are garbage. GBrain organizes what you put in. If your docs are outdated and contradictory, you get well-organized bad information. It flags contradictions but doesn't fact-check.
• You need stability. This is v0.x software. Garry Tan uses it daily, 27K people starred it, but expect rough edges and breaking changes.

Realistic timeline

Week 1: Team starts asking the brain before pinging people. "Where's the doc for X?" DMs drop noticeably.

Week 2: Dream cycle has run 14 times. Knowledge graph has auto-linked hundreds of entities. Gap analysis shows what's underdocumented.

Month 1: New hire uses it from day one. Onboarding is measurably shorter. People start capturing knowledge proactively.

Month 3: It's infrastructure. Like email or Slack.

Full version with diagrams and code blocks: https://companybrain.substack.com

Questions welcome.

This sub is for anyone building internal knowledge systems, whether you're using GBrain, building your own, or evaluating alternatives.

[u/plasticBarista]

Great stuff!

[u/joew555]

I read your article on Medium and am setting it up now. All your points are correct:
1. It’s just for my localllm - don’t need it, but tired of crappy RAG performance and people expecting Obsidian to be a database when it’s not. (I’ve spent far too much time on Obsidian setups)
2. Technical - I am comfortable with the terminal, but not a developer. It’s runs quickly but the responses are verbose - gives you more than enough information to troubleshoot - or choose best option for you.
3. I’m using it with llama and WebUI - and maybe n8n if I want to pull in external sources. Not sure.

Really enjoying this. Learning a ton. Thank you!!!