Claude Sonnet 4

Claims and evidence

• Released 22 May 2025 ● Primary source[1] [3]May 22, 2025
• Deprecated 14 April 2026 ● Primary source[4]2026-04-14: Claude Sonnet 4 and Claude Opus 4 models [3]April 14, 2026
• Retired 15 June 2026 ● Primary source[4]2026-04-14: Claude Sonnet 4 and Claude Opus 4 models [3]June 15, 2026

• Status Retired ● Primary source[4]Model status
• Replaced by Claude Sonnet 4.6Recommended replacement as listed on the deprecations page when checked on 2026-10-01. ● Primary source[4]2026-04-14: Claude Sonnet 4 and Claude Opus 4 models

• Successor of Claude 3.7 Sonnet ● Primary source[1]

• Change · Tool use Can use tools such as web search during extended thinking; this was in beta at launch.Compared with Claude 3.7 Sonnet ● Primary source[1]
• Change · Reasoning Long thought processes are condensed by a smaller model, where Claude 3.7 Sonnet always showed its raw thinking; Anthropic says this is needed in about 5% of cases.Compared with Claude 3.7 Sonnet ● Primary source[5] [1]
• Change · Training data Training data includes public web data as of March 2025, against November 2024 for Claude 3.7 Sonnet.Compared with Claude 3.7 Sonnet ● Primary source[5] [6]
• Change · Context length A 1M-token context window was offered in beta from 2025-08-12, after launch; Anthropic ended that beta for this model on 2026-04-30.Compared with Claude 3.7 Sonnet ● Primary source[3]August 12, 2025; March 30, 2026; April 30, 2026

• Input text, image ● Primary source[2]Claude Opus 4 and Claude Sonnet 4 Summary Table, Modalities
• Output textThe model report also mentions audio output through text-to-speech in the Claude apps. ● Primary source[2]Claude Opus 4 and Claude Sonnet 4 Summary Table, Modalities
• Feature Reasoning mode ● Primary source[1] [5]section 1.1.2
• Context window 200k tokensA 1M-token window was in beta from 2025-08-12 and was retired for this model on 2026-04-30. ● Primary source[3]March 30, 2026
• Parameters Not disclosedNot disclosed by Anthropic. No claim madeNo source
• Access consumer app, API, cloud partner ● Primary source[1]

Lineage

Variants

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