What is the difference between Claude, GPT, and Gemini?

Claude, GPT, and Gemini are the three frontier large language model (LLM) families from Anthropic, OpenAI, and Google DeepMind respectively. All three are transformer-based decoder architectures trained on web-scale text plus reinforcement learning from human feedback (RLHF), but they diverge in training philosophy, modality, context length, deployment surface, and safety methodology.

Anthropic's Claude family (Claude 3.5 Sonnet, Claude 3.7 Sonnet, Claude Sonnet 4, Claude Opus 4) is trained using Constitutional AI (Bai et al., arXiv:2212.08073), a method that uses a written constitution and AI-generated feedback (RLAIF) to shape model behavior, in contrast to OpenAI's heavier reliance on human labelers. Anthropic publishes a Responsible Scaling Policy and AI Safety Level (ASL) framework. Claude 3.5 Sonnet introduced Computer Use in October 2024 — the first frontier model that controls a desktop via screenshots, mouse, and keyboard. Claude models support a 200,000-token context window in production and lead the SWE-bench Verified coding benchmark as of 2025.

OpenAI's GPT family (GPT-4o, GPT-4.1, GPT-4.5, plus the o-series reasoning models o1, o3, o3-mini, o4-mini) is the most widely deployed via ChatGPT and the OpenAI API. GPT-4o, released May 2024, is natively multimodal across text, vision, and audio, with sub-320ms audio response latency. The o-series introduced large-scale reinforcement-learned chain-of-thought at inference, achieving 83.3% on AIME 2024 versus ~13% for GPT-4o. GPT-4.1 (April 2025) extended context to 1 million tokens. OpenAI's safety stack uses RLHF, a Preparedness Framework, and red-teaming via the System Card process.

Google DeepMind's Gemini (1.0 Ultra/Pro/Nano, 1.5 Pro/Flash, 2.0 Flash, 2.5 Pro) is described as "natively multimodal" — trained from scratch on interleaved text, image, audio, video, and code (Gemini Technical Report, arXiv:2312.11805). Gemini 1.5 Pro shipped the first 1M-token production context window in February 2024 and was later extended to 2M tokens, using a sparse Mixture-of-Experts (MoE) architecture. Gemini 2.5 Pro (March 2025) introduced "thinking" reasoning and topped LMArena. Gemini is deeply integrated into Google Search (AI Overviews), Workspace, Android, and Vertex AI.

The three families differ most sharply on (1) safety method — Anthropic's Constitutional AI vs OpenAI's RLHF + Preparedness vs Google's Frontier Safety Framework; (2) context length— Gemini 2M > GPT-4.1 1M > Claude 200K; (3) distribution — ChatGPT consumer scale, Gemini Workspace/Search integration, Claude API + Bedrock + Vertex enterprise; and (4) reasoning approach — OpenAI's o-series and Gemini 2.5 use explicit inference-time thinking tokens, while Claude offers an "extended thinking" mode introduced in Claude 3.7 Sonnet.