OpenAI: GPT-5.6 Terra

GPT-5.6 Terra is a balanced model in OpenAI's GPT-5.6 series, positioned between the flagship Sol tier and the cost-efficient Luna tier. It suits everyday coding, reasoning, and agentic tasks where capability and cost need to be balanced, at roughly half the cost of Sol.

OpenAI: GPT-5.6 Sol

GPT-5.6 Sol is the flagship model in OpenAI's GPT-5.6 series, suited for complex reasoning, coding, and agentic workflows. It is particularly strong at command-line and multi-step coding tasks and long-horizon problem solving.

OpenAI: GPT-5.6 Luna Pro

GPT-5.6 Luna Pro is the same underlying model as GPT-5.6 Luna, served with reasoning mode set to pro for higher-quality responses on complex tasks.

GPT-5 Pro

GPT-5 Pro is OpenAI’s most advanced model, offering major improvements in reasoning, code quality, and user experience. Optimized for complex, high-stakes tasks that demand step-by-step reasoning, instruction following, and accuracy. Supports test-time routing controls and advanced prompt understanding, including intent cues like "think hard about this". Delivers reduced hallucination, lower sycophancy, and stronger performance across coding, writing, and health-related workloads.

GPT-5

OpenAI’s most advanced model, offering major improvements in reasoning, code quality, and user experience. Optimized for complex tasks that require step-by-step reasoning, instruction following, and accuracy in high-stakes use cases. Supports test-time routing and advanced prompt understanding (e.g., "think hard about this"). Reductions in hallucination/sycophancy with better performance in coding, writing, and health-related tasks.

GPT-4.1

GPT-4.1 is a flagship large language model optimized for advanced instruction following, real-world software engineering, and long-context reasoning. It supports a 1 million token context window and outperforms GPT-4o and GPT-4.5 across coding (54.6% SWE-bench Verified), instruction compliance (87.4% IFEval), and multimodal understanding benchmarks. It is tuned for precise code diffs, agent reliability, and high recall in large document contexts, making it ideal for agents, IDE tooling, and enterprise knowledge retrieval.

OpenAI: GPT-5.6 Terra

GPT-5.6 Terra is a balanced model in OpenAI's GPT-5.6 series, positioned between the flagship Sol tier and the cost-efficient Luna tier. It suits everyday coding, reasoning, and agentic tasks where capability and cost need to be balanced, at roughly half the cost of Sol.

OpenAI: GPT-5.6 Sol

GPT-5.6 Sol is the flagship model in OpenAI's GPT-5.6 series, suited for complex reasoning, coding, and agentic workflows. It is particularly strong at command-line and multi-step coding tasks and long-horizon problem solving.

OpenAI: GPT-5.6 Luna Pro

GPT-5.6 Luna Pro is the same underlying model as GPT-5.6 Luna, served with reasoning mode set to pro for higher-quality responses on complex tasks.

GPT-5 Pro

GPT-5 Pro is OpenAI’s most advanced model, offering major improvements in reasoning, code quality, and user experience. Optimized for complex, high-stakes tasks that demand step-by-step reasoning, instruction following, and accuracy. Supports test-time routing controls and advanced prompt understanding, including intent cues like "think hard about this". Delivers reduced hallucination, lower sycophancy, and stronger performance across coding, writing, and health-related workloads.

GPT-5

OpenAI’s most advanced model, offering major improvements in reasoning, code quality, and user experience. Optimized for complex tasks that require step-by-step reasoning, instruction following, and accuracy in high-stakes use cases. Supports test-time routing and advanced prompt understanding (e.g., "think hard about this"). Reductions in hallucination/sycophancy with better performance in coding, writing, and health-related tasks.

GPT-4.1

GPT-4.1 is a flagship large language model optimized for advanced instruction following, real-world software engineering, and long-context reasoning. It supports a 1 million token context window and outperforms GPT-4o and GPT-4.5 across coding (54.6% SWE-bench Verified), instruction compliance (87.4% IFEval), and multimodal understanding benchmarks. It is tuned for precise code diffs, agent reliability, and high recall in large document contexts, making it ideal for agents, IDE tooling, and enterprise knowledge retrieval.