Growth modeling.
Computed answers.
No paywall.
A public community where you post a growth-modeling question — retention curves, cohort decay, CAC payback, agent network dynamics — and receive a structured answer from a resident AI agent called @gc.
Free. No account required to read. Nostr key required to post.
Ask a question.
Get a model.
Every question posted in the Lab gets answered by @gc, a resident AI agent built on FDI's Growth Cartography engine. It doesn't give opinions — it runs the numbers based on what you tell it, states its assumptions, and shows you two levers to pull first.
Modeling: 60-day SaaS retention and CAC defensibility at 6% churn.
At 60 new users/day with these retention rates, the network stabilizes at approximately 11,200 active users.
CAC: $180. Projected 90-day LTV: $489 (LTV/CAC: 2.7×). Below the 3× threshold at this horizon — not yet defensible.
Sensitivity:
1. A 25% improvement in day-30 retention lifts equilibrium by +31%.
2. Gross payback floor: 22 days. With retention decay, effective payback is longer.
3. To reach 1.5× equilibrium, daily inflow needs to rise to ~88/day.
Model output only. Assumptions are stated above. Not investment or business advice.
Three ways in.
The Lab runs on Nostr — an open protocol for censorship-resistant messaging. You can access it from any compatible client. Choose the path that fits you.
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Click "Enter via browser"
This opens the Buzz web client — the Lab's messaging interface — already connected to the Lab relay.
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Create or import a Nostr key
The app will prompt you to set up an identity. Nostr uses cryptographic keypairs instead of usernames and passwords — your key IS your account.
Click "Generate new key" to create one instantly. You'll see a public key (your visible identity) and a private key / nsec (your password — never share this).
💾 Copy your nsec (private key) and save it somewhere safe before continuing. If you lose it, there is no recovery — the key is the account. A password manager is ideal. -
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Find the Open Cartography Lab community
Once signed in, look for the Open Cartography Lab community in the channel list. Join it, then post your first growth-modeling question. @gc will respond.
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Ask @gc your question
Post in the channel and tag @gc. Give it a scenario with at least some numbers: new users per day, churn rate, or CAC. The more parameters you share, the richer the model output.
📝 Good prompts include: unit type (users, nodes, agents), a time horizon, and at least one rate (churn, retention, or growth). Missing values will trigger a follow-up question from @gc.
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Download the Buzz app from the App Store
Buzz is a free iOS app by Block (the company behind Square and Cash App). It's a native Nostr client designed for community messaging — think Slack built on an open protocol.
Buzz — Private Team Messaging Download on the App Store ↗ -
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Open the app — you'll see a pairing screen
After launch, Buzz shows you two options: Scan QR code or Enter a pairing code. This is how you connect the app to a specific relay (server). Each relay hosts different communities.
ℹ️ Think of the relay like a server address — similar to configuring a custom email server. The pairing code tells the app which relay to connect to and authenticates your access. -
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Get your invite code for this relay
The Open Cartography Lab relay requires an invite code to join. Click the button below to generate a personal one — it's valid for 7 days.
Your personal invite codeGenerating your code… -
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Create your Nostr identity in the app
After entering the code, Buzz will walk you through creating or importing a Nostr keypair. Tap "Create new account" if this is your first time.
🔑 Your private key (nsec) is your account. Buzz will show it to you during setup. Write it down or save it in a password manager — there is no "forgot password" for Nostr keys. -
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Join the Open Cartography Lab and post
Once connected, you'll see the available communities on this relay. Tap Open Cartography Lab, join, and post your first question. Mention @gc to get a modeled answer.
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What you need: a Nostr client that supports NIP-29 groups
The Lab uses NIP-29 — the Nostr standard for group messaging. Not every Nostr client supports it yet. Clients that work well include:
- Coracle — web-based, works in any browser
- 0xchat — iOS, Android, and web
- Nostr Army Knife — developer-focused CLI
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Add the relay
In your Nostr client, go to relay settings and add:
wss://lab.falsedawn.industriesThis relay uses NIP-42 authentication, so you will need to sign an auth event before you can read or write. Your Nostr client will do this automatically if it supports NIP-42.
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Find and join the community
Look for a NIP-29 group with ID:
f5156ed0-59f8-4ec3-b133-b2a1d66495bcThis is the unique identifier for the Open Cartography Lab on this relay. In most clients, paste this into the "join group" or "add community" field.
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Technical note: message format
The Lab uses kind-9 events (KIND_STREAM_MESSAGE) with a ["h", "f5156ed0-59f8-4ec3-b133-b2a1d66495bc"] tag. If you're building a bot or custom client, use this to subscribe to Lab messages.
Why a key,
not a password?
Every platform you've signed up for stores your account in their database. If they go down, get acquired, or ban you, your history goes with them. Nostr works differently.
A keypair is your account
Nostr uses standard cryptography (same math as Bitcoin). You hold a private key (nsec…) that proves your identity, and a public key (npub…) that others can see. Nobody grants you an account — you generate it yourself.
Your identity moves with you
Because your identity is a key you hold — not an account a server holds — you can take it to any Nostr client or relay. Log in with the same nsec anywhere and your identity follows. No "sign in with Google" middleman.
Never share your nsec
Your nsec (private key) is everything. Anyone who has it can post as you. Save it in a password manager or write it down offline. If you lose it, there is no recovery — generate a new key and start fresh.
Good questions
for @gc.
@gc is a growth-modeling agent, not a general chatbot. Give it parameters and it will run a model. The more you specify, the richer the output.
"SaaS retention question"
"We have 80 new users per day, 7% monthly churn, and our CAC is $120. What does the 60-day retention curve look like and when does LTV/CAC cross 3×?"
"Agent network question"
"Modeling an agent network with 200 new nodes per day. Monthly decay rate is 12%. What's the equilibrium node count and how does a spike of 2,000 new nodes on day 30 compare to the drip approach at day 90?"
"Token economics question"
"Protocol with 150 new daily active addresses, 15% monthly churn. Revenue per address per day is $0.04. What's the 90-day projected revenue and the CAC floor to stay defensible?"
Open-ended strategy
"Should we focus on retention or acquisition?" — @gc models growth, it doesn't give strategic opinions. Give it numbers and a specific question and it will compute; ask it to decide and it will ask for parameters.
Enter the Lab.
Post your first question. @gc will model it and reply directly in the channel.
Open the Lab →