Anthropic LLM Medium Closed weights

Claude Sonnet 5

135 days since Anthropic announced it · 30 Jun 2026

Claude Sonnet 5 is a closed-weights LLM from Anthropic, announced 30 Jun 2026. It costs $2 per 1M input tokens and $10 per 1M output tokens. Its context window is 1M tokens.

Input: $2; per 1M tokens
Cache write: $2.50; per 1M tokens
Cache read: $0.20; per 1M tokens
Output: $10; per 1M tokens
Context window: 1M; tokens
Parameters: —; not disclosed

Announcement: anthropic.com/news/claude-sonnet-5
Docs: platform.claude.com/docs/en/models/sonnet-5/overview

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Anthropic · Medium

closed weights

Claude Sonnet 5.5 +90d 28 Sep 2026
Claude Sonnet 5 +133d 30 Jun 2026
Claude Sonnet 4.6 +141d 17 Feb 2026
Claude Sonnet 4.5 29 Sep 2025