Bring your AI key¶
Bartimaeus thinks with an AI model — and you connect the model yourself. Your own provider key means the model bill goes to your provider account, at your provider's price, and your key stays encrypted in our vault. This page walks through the wizard end to end: it is the one setup step that needs a little care, and it takes about three minutes.
Why your own key¶
An AI model — the thing that reads your request and figures out how to do it — is paid for per use. Instead of bundling a model into the price and metering you for it, Bartimaeus uses the key you bring:
- The model bill is yours. You top up your provider account and pay their published rates. Bartimaeus adds nothing on top, ever.
- You choose the model. One key from a provider like OpenRouter can reach hundreds of models; you pick what your agent thinks with, and you can change it later.
- Your key is protected. It is stored encrypted under a key that belongs to your account only, it is never shown to the model, and it is never written to logs.
What a key actually is¶
A key is a long code from your model provider's console — it looks something
like sk-... or a similar string. It is not:
- your Bartimaeus account (there is no password to reuse here),
- a login for your email or calendar (those are connected separately and ask for their own permission), or
- a payment method (providers bill the card on your provider account, not through Bartimaeus).
Step 1 — choose a provider¶
Open Settings → Models in Bartimaeus, or the Get started panel if you are new. The wizard lists providers in a recommended order, with more below. The first five are:
| Provider | Get a key |
|---|---|
| OpenRouter (recommended — one key, many models) | openrouter.ai/keys |
| Anthropic | console.anthropic.com |
| OpenAI | platform.openai.com |
| aistudio.google.com | |
| DeepSeek | platform.deepseek.com |
Every row in the wizard carries a Get a key link that opens the provider's own console directly — the links here match them. If your provider is not in the first five, it will be further down the same list.
Step 2 — create and copy the key¶
In the provider's console:
- Open the provider's key page (via the Get a key link).
- Create a new key — give it a name you will recognise, like "Bartimaeus".
- Copy it straight away. Some providers show a key only once; if you miss it, delete that key and make another — it costs nothing.
Step 3 — paste it into Bartimaeus¶
Back in the wizard, choose Paste, put the key in the field (there is a show/hide toggle if you want to check it), and tap Save and check.
The check is a small, free metadata call to the provider — nothing is billed, and no personal data is sent. It tells you honestly whether the key works:
- Accepted. You will see "Key accepted — the provider answered." Your provider's model becomes your default only if you do not already have a default set — so a fresh setup ends ready to use, and an existing setup is never quietly changed.
- Rejected. You will see: "That key was not accepted. Copy it again from your provider console and check for missing characters or an extra space. If you saved a working key before, it is still in place — nothing was replaced." Use Try again with a fresh copy, or Different provider. Nothing else changes while you retry.
- Saved, check not run. If the provider could not be reached at that moment, the key is saved but unverified — "Saved — the provider check could not run just now." Try the check again in a few minutes.
Choosing your model¶
After the key is accepted, the provider's default model is ready to use. To change it, use the model picker — it is searchable — from Settings or from the composer in a conversation. You can switch models as often as you like; each provider's prices are set by the provider, not by us, so the model bill page explains where to look.
Looking after your key¶
- To replace a key: open the provider's row in Settings → Models and paste the new one. If the new key fails its check, your previous working key stays in place.
- To remove a key: remove it from the same screen. Without a key, Bartimaeus will tell you plainly that it cannot think — nothing pretends to work when it cannot (this is deliberate: the Free plan also needs a key).
- Never share a key. Treat it like a bank card number. If one leaks, delete it in the provider's console; the old key stops working immediately.
- What we never do with it: we do not use it for anything except calling the model provider you chose, we do not show it to the model, and we do not write it to logs. The Privacy Policy and security model set out the rest.
If something goes wrong¶
The Troubleshooting page covers rejected keys, provider checks that will not run, and what a provider outage looks like from your side. When the key is accepted, the next step is your first chat.