Anthropic releases Claude Sonnet 5

Background

Sonnet is the middle tier of the Claude model family, between the larger Opus models and the smaller Haiku models.

What happened

On 30 June 2026 Anthropic released Claude Sonnet 5, which it described as its most agentic Sonnet model. ^[1]

The model launched at an introductory price of $2 per million input tokens and $10 per million output tokens. ^[1]

Anthropic said Sonnet 5 came close to Opus 4.8 in performance at lower prices. ^[1]

Key details

Sonnet 5 became the default model for Free and Pro users. ^[1]

On 10 August 2026 the introductory price was made permanent, which cancelled a scheduled rise to $3 and $15. ^[1][2]

Rate limits are caps on how much a user or organisation can send within a set period, and raising them lets people run more requests before hitting the cap. A default model is the one that a chat product uses unless the user picks another. An introductory price is a launch price offered for a set time, which a company can later make permanent or replace.

Impact

Rate limits rose across Claude Chat, Cowork, Claude Code and the Claude Platform. ^[1]