Choose the right model for your AI agent
CustomGPT.ai offers multiple AI models to power your agent. This guide helps you select the best model for your specific needs.
Available Models
This is the summary of models that will help you get the most out of your AI agent:
| Model | Best For | Speed | Availability |
|---|---|---|---|
| GPT-4.1 ⭐ | General use, recommended default | Fast | All plans |
| GPT-4o mini | High-volume, sub-second responses | Fastest | Premium |
| GPT-5.1 | Complex reasoning tasks | Moderate | Premium |
| Claude Sonnet 4.5 | Advanced intelligence + natural dialogue | Moderate | Enterprise |
| Claude Opus 4.5 | Most capable model available | Slower | Enterprise |
For the full list of available models, please check this article: Available AI models and capabilities
GPT-4.1 ⭐ Recommended Default
The best choice for most use cases. GPT-4.1 delivers reliable performance for ticket deflection, internal search, research assistance, and customer engagement.
Recommended for:
- Ticket deflection and customer support agents
- Internal knowledge base search
- Employee onboarding and training assistants
- Research assistants
- Lead engagement and pre-sales support
Start here unless you have a specific reason to choose another model.
Supported agent capabilities: Optimal Choice, Highest Relevance, Complex Reasoning.
GPT-4o mini
Optimized for sub-second response times, at the cost of reduced intelligence.
Recommended for:
- Instant responses (under 1 second)
- Simple lookups and quick conversations
Trade-off: Less sophisticated than GPT-4.1. Not recommended for complex analysis or nuanced conversations. Increases hallucination likelihood.
Supported agent capabilities: Fastest Responses.
GPT-5.1
Advanced reasoning model for complex, multi-step problems.
Recommended for:
- Analysis requiring deeper insights
- Complex interpretation and cross-linking content
- Tasks requiring sophisticated reasoning
Trade-off: Slower response times than GPT-4.1. Best for quality-critical applications where users will wait a little bit more for better answers.
Supported agent capabilities: Optimal Choice (Enterprise), Highest Relevance(Enterprise), Complex Reasoning(Premium & Enterprise).
Claude Sonnet 4.5
Anthropic's advanced model combining high intelligence with natural, human-like communication.
Key advantage: Higher accuracy than GPT-4.1 on many tasks, with excellent conversational quality.
Recommended for:
- Premium customer experiences requiring empathy
- Nuanced, context-sensitive conversations
- High-quality content generation
- Sophisticated dialogue handling
Trade-off: Slightly slower than GPT-4.1. Enterprise plans only.
Supported agent capabilities: Optimal Choice, Highest Relevance, Complex Reasoning.
Claude Opus 4.5
Anthropic's most advanced model. Engineered for complex problem-solving, sophisticated reasoning, and navigating ambiguous scenarios where context and nuance are critical.
Recommended for:
- Mission-critical analysis and decisions
- Complex scenarios with competing priorities
- Highest possible accuracy and insight
- Tasks where other models fall short
Trade-off: Higher query cost and potential added latency.
Supported agent capabilities: Optimal Choice, Highest Relevance, Complex Reasoning.
Updated 4 days ago