> ## Documentation Index
> Fetch the complete documentation index at: https://docs.chatref.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Choosing a Model

> Chatref is multi-model – pick the right AI model for each agent from four tiers, balancing cost and reasoning power.

Chatref is **multi-model**: you can pick any AI model for each agent. Models are
grouped into four tiers, from cheap-and-fast to deep-reasoning. You choose in the
**Playground**, so each bot can run on the model that fits its job.

The default model is **GPT-5.4 Mini**. It handles everyday support well, so most
bots never need to change it.

## The four tiers

Pricier tiers cost a little more per message but reason more deeply. Start low and
move up only if your bot's answers need it.

| Tier         | Good for                                   | Example models                                                                      |
| ------------ | ------------------------------------------ | ----------------------------------------------------------------------------------- |
| **Budget**   | Simple FAQs – the cheapest option          | GPT-4o Mini, GPT-5.4 Nano, Gemini 3.1 Flash Lite, Llama 4 Maverick, DeepSeek V4 Pro |
| **Standard** | Everyday support – the default             | GPT-5.4 Mini (default), Kimi K2.6, Grok 4.3, Gemini 3.5 Flash                       |
| **Premium**  | Trickier questions that need more thinking | GPT-4.1, GPT-5.4, Gemini 3.1 Pro, Claude Sonnet 4.6                                 |
| **Flagship** | The hardest reasoning                      | Claude Opus 4.8, GPT-5.5                                                            |

Models come from seven providers – **OpenAI**, **Anthropic**, **Google**, **xAI**,
**Meta**, **DeepSeek**, and **Moonshot** – all available from the same dropdown.

## How cost works

Your bot spends from your balance each time it answers, priced by the AI it uses.
Higher tiers cost more per message than lower ones. A dental clinic answering
routine "What are your hours?" questions does fine on a Budget or Standard model,
while a SaaS app fielding deep technical questions may earn its keep on Premium.

See [How Pricing Works](/billing/how-pricing-works) for the full picture.

## How to change the model

<Steps>
  <Step title="Open the Playground" icon="bolt">
    Go to your agent and open the **Playground**.
  </Step>

  <Step title="Pick a model">
    In the left panel, open the **Model** dropdown. Models are grouped by tier –
    pick the one you want.
  </Step>

  <Step title="Deploy">
    Click **Deploy** to save it. Test a few questions in the live preview to see
    how the new model answers.
  </Step>
</Steps>

<Tip>
  Start with the default. Only move up a tier if your bot's answers need deeper
  reasoning – it's the simplest way to keep costs down.
</Tip>

## Next steps

<CardGroup cols={2}>
  <Card title="The Playground" icon="bolt" href="/agents/playground">
    Where you pick the model and test how it answers.
  </Card>

  <Card title="How Pricing Works" icon="wallet" href="/billing/how-pricing-works">
    See how each message is priced by the model and tokens used.
  </Card>
</CardGroup>