---
updatedAt: 2026-06-09T16:56:26.000Z
---

Fetch the complete documentation index at: https://docs.customgpt.ai/llms.txt. Use this file to discover all available pages before exploring further. Append .md to any documentation page URL to get its markdown version.

# Available AI models and capabilities

This guide lists all AI models and agent capabilities avaiable for your AI agent. You can customize your agent’s capabilities by choosing the model that fits your goals.

## Standard Users

Standard users have access to the **Optimal** agent capability which comes with a **GPT-4.1** model.

**Optimal** delivers balanced performance for accuracy, speed, and intelligence, ideal for most general-purpose use cases.

## Premium Users

In addition to **Optimal**, Premium users can switch between three additional capabilities:

* **[Speed](https://docs.customgpt.ai/docs/how-to-use-fast-responses-mode-for-your-ai-agent#/)** – Uses **GPT-4o mini** and optimized for shorter, faster replies and high responsiveness.
* **[Accuracy](https://docs.customgpt.ai/docs/how-to-use-advanced-reasoning-for-your-ai-agent#/)** – Uses **GPT-4.1** and optimizes how the AI agent selects and uses contextual information from your data.
* **[Understanding](https://docs.customgpt.ai/docs/how-to-configure-and-use-complex-tasks-in-customgptai#/)** – Uses **GPT-5.1 Optimal** for deeper reasoning, structured problem-solving, and more analytical or technical interactions.

## Enterprise Users

Enterprise users can fully customize which AI model powers each agent. This includes access to the most advanced GPT and Claude models optimized for different use cases and reasoning needs.

* **Speed**: GPT-4o mini, GPT-4.1 mini and Claude 4.5 Haiku, Gemini 3.5 Flash.
* **Optimal**: GPT-4.1, GPT-4o, GPT-5.1 Optimal, GPT-5.1 Smart, GPT-5.2 Optimal, GPT-5.2 Smart, GPT-5.4, GPT-4.1 mini, GPT-4o mini, Claude 4.5 Opus, Claude 4.6 Opus, Claude 4.8 Opus, Claude 4.5 Sonnet, Claude 4.6 Sonnet, Claude 4.5 Haiku, Gemini 3.5 Flash, Gemini 3 Pro, and Gemini 3.1.
* **Accuracy**: GPT-4.1, GPT-4o, GPT-5.1 Optimal, GPT-5.1 Smart, GPT-5.2 Optimal, GPT-5.2 Smart, GPT-5.4, GPT-4.1 mini, GPT-4o mini, Claude 4.5 Opus, Claude 4.6 Opus, Claude 4.8 Opus, Claude 4.5 Sonnet, Claude 4.6 Sonnet, Claude 4.5 Haiku, Gemini 3 Pro, and Gemini 3.1.
* **Understanding**: GPT-4.1, GPT-4o, GPT-5.1 Optimal, GPT-5.1 Smart, GPT-5.2 Optimal, GPT-5.2 Smart, GPT-5.4, Claude 4.5 Opus, Claude 4.6 Opus, Claude 4.8 Opus, Claude 4.5 Sonnet, Claude 4.6 Sonnet, Gemini 3 Pro, and Gemini 3.1.

<br />