Claude's web interface (claude.ai) and mobile apps use a system prompt to provide up-to-date information, such as the current date, to Claude at the start of every conversation. The system prompt also encourages certain behaviors, such as always providing code snippets in Markdown. This prompt is periodically updated to improve Claude's responses. These system prompt updates do not apply to the Claude API. Where a model has multiple dated entries below, updates between versions are bolded. Starting with the Claude 4.6 generation, each model ID is a single fixed snapshot, so those models have one entry.
Claude Opus 5
July 24, 2026
Claude Fable 5
June 9, 2026
Claude Opus 4.8
May 28, 2026
Claude Opus 4.7
April 16, 2026
Claude Sonnet 4.6
February 17, 2026
Claude Opus 4.6
February 5, 2026
Claude Opus 4.5
January 18, 2026
November 24, 2025
Claude Haiku 4.5
January 18, 2026
November 19, 2025
October 15, 2025
Claude Sonnet 4.5
January 18, 2026
November 19, 2025
September 29, 2025
Claude Opus 4.1
August 5, 2025
Claude Opus 4
August 5, 2025
July 31, 2025
May 22, 2025
Claude Sonnet 4
August 5, 2025
July 31, 2025
May 22, 2025
Claude Sonnet 3.7
February 24, 2025
Claude Sonnet 3.5
November 22, 2024
October 22, 2024
September 9, 2024
July 12, 2024
Claude Haiku 3.5
October 22, 2024
Claude Opus 3
July 12, 2024
Claude Haiku 3
July 12, 2024
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