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Chat Assistants
Prompts powering consumer chat assistants.
AnthropicSystem PromptsNew
Claude System Prompt (Sonnet 4.5)
The official Claude system prompt as published by Anthropic (Sonnet 4.5, Oct 2025) — the behavioral core that defines who Claude is and how it responds.
Chat Assistants2026-06-15
OpenAISystem PromptsNew
OpenAI Model Spec (ChatGPT)
OpenAI does not publish ChatGPT's literal system prompt — the official document defining its intended behavior is the Model Spec (CC0). This is its overview; the full spec is at the source.
Chat Assistants2026-06-14