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Bring your own Google AI Studio key to use Gemini in Rumus — including the long-context Pro models and the fast Flash variants.

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Before you start

You need:
  • A Google account.
  • An API key from Google AI Studio.
  • Billing enabled on your Google AI project for paid models. Some Gemini models are available on a free tier with limits.
For Vertex AI (the Google Cloud enterprise endpoint), use the OpenAI-compatible provider — Vertex requires service-account auth that’s outside the scope of this provider type.

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Add Google AI in Rumus

1

Open the model settings

Go to Settings → AI → Models and click Add Model.
2

Pick the provider

Set Provider to Google AI.
3

Paste your API key

Paste the key from Google AI Studio into API Key. It’s stored encrypted in your local vault.
4

(Optional) Custom base URL

Leave Base URL blank to use https://generativelanguage.googleapis.com. Override only for special routing.
5

Pick a model

Choose from the list (Gemini 3 Pro, Gemini 3 Flash, Gemini 2.5 Pro/Flash, etc.) or toggle Enter custom ID to type a model ID manually.
6

Capabilities

On the Capabilities tab:
  • Tool Calling — Gemini supports function calling.
  • Vision — Gemini is natively multimodal.
  • Prompt Cache — supported on the Pro tier.
7

Save

The model appears in the picker under Custom Models.
Gemini Pro models accept extremely large contexts (up to 1M tokens on some versions), which is useful for reading entire repositories or long log files in a single pass.

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Tips

  • Thinking budget is configurable per request on Pro models — Rumus exposes it as a per-thread setting next to temperature.
  • System instructions are honored, but Gemini treats them slightly differently from OpenAI; use them for stable rules, put dynamic context in the user message.
  • Region matters for latency. If you’re far from us-central1, expect noticeable round-trip times on streaming responses.

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Troubleshooting

The API key is invalid or doesn’t have the Generative Language API enabled. Re-create it in Google AI Studio.
You’ve hit the free-tier quota or a per-minute limit. Enable billing on the Google project or wait for the window to reset.
Toggle Enter custom ID and paste the exact model ID (e.g. gemini-3-pro-preview-12-01).
Hit a snag we didn’t cover? Ask in the Rumus community.

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Next steps

Other providers

Anthropic, OpenAI, Z.AI, DeepSeek, Kimi, Ollama, OpenAI-compatible.

AI assistant

What you can do once a model is connected.