Anthropic releases Claude Sonnet 5, “the most agentic Sonnet yet”
Confirmed
The takeaway
Claude Sonnet 5 (claude-sonnet-5) launched on June 30, 2026 at $2/$10 per million tokens.
Status
- Claim
Confirmed
- Our reporting
- High confidence
- Importance
- 3 of 5
- Last verified
- 29 September 2026
Your AI and this story
- GPT-6 Astra61 days after its cutoff
- Claude Opus 5.5In its training data
- Gemini 4 Hydrogen91 days after its cutoff
- Grok 4.730 days after its cutoff
It is after the cutoff of GPT-6 Astra, Gemini 4 Hydrogen and Grok 4.7, and can be in the training data of Claude Opus 5.5.
Key facts
- Released June 30, 2026; model id claude-sonnet-5; context 1M, 128K output
- Price $2 input / $10 output per 1M tokens (introduced as through-Aug-31 pricing; Anthropic’s page says it was made permanent Aug 10, 2026)
- Humanity’s Last Exam with tools: 51.2% vs Sonnet 4.6’s 46.8% (Anthropic)
- Default model for Free and Pro plans from July 1, 2026, replacing Sonnet 4.6
- Cyber safeguards enabled by default
What happened
Sonnet 5 can make plans, use browsers and terminals, run autonomously, and check its own output without being asked. It is on the Claude API, Claude Platform on AWS, Bedrock and Microsoft Foundry, with Google Cloud following. Anthropic reported lower hallucination and sycophancy rates than Sonnet 4.6.
Why it matters
It moved Opus-4.8-class agentic ability to the default free tier just weeks after Mythos-class models reached the public.
Sources
5 sources from 4 sites. Numbers match the chips in the text.
5 sources: 3 primary, 2 press
Primary
- Introducing Claude Sonnet 5 (Anthropic)anthropic.com, official
- Claude Sonnet 5 System Cardanthropic.com, paper
- Claude Sonnet 5 docs overviewplatform.claude.com, docs
Press
- TechCrunch: Claude Sonnet 5 as a cheaper way to run agentstechcrunch.com, press
- MacRumors: Sonnet 5 with near-Opus performancemacrumors.com, press
Changes
- Filed
