Frequently asked questions
Is Build Familiar free?
Yes. Building is free for students, with no paywalls on core building. You bring your own API key, so you pay your own inference costs directly to your provider — the site never marks them up.
Do I need my own API key?
Yes. You bring your own API key. Keys never land in logs and aren't persisted beyond your session unless you explicitly opt in.
What is the guardrail gate?
A mandatory safety check every agent passes before touching anything real: input filtering, output checking, and human approval for irreversible actions. You also get a guardrail report for every agent you ship.
Can I skip the guardrail gate?
No. Guard is never skipped. It's the doorway every agent walks through before acting in the real world.
What happens in the sandbox?
You test your agent against simulated scenarios before any real-world action. Nothing irreversible happens until you've seen your agent behave safely.
Where does my agent deploy?
To your own API key and infrastructure. The site hosts the guardrail wrapper, not your inference bill.
How does this relate to the Prompt Engineering courses?
Build Familiar is Part 3 of the trilogy. Part 1 (Prompt Engineering) teaches you to write great prompts; Part 2 (Advanced Prompt Engineering) teaches agentic patterns like ReAct and guardrails theory; Part 3 is where you build and ship a real guarded agent. See the trilogy.
Do you store my API key?
No — not beyond your session, and never in logs. See Privacy.
Where is my API key kept?
Only in your browser. By default it lives in memory and vanishes when the tab closes. If you tick "Remember on this device", it's stored in your browser's local storage — still only on your device. Manage it any time at Your API key.
Which providers work?
Any OpenAI-compatible API. The default is OpenAI's endpoint, but you can point it at any compatible provider by changing the base URL on the key page.