---
id: "2026-06-30-claude-sonnet-5"
url: "https://postcutoff.com/e/2026-06-30-claude-sonnet-5/"
as_of: "2026-11-13T13:49:00+01:00"
date: "2026-06-30"
date_precision: day
category: model-release
importance: 3
confidence: high
status: [Confirmed]
sources: 5
editor: human editor
human_review: null
version: "2026-10-04"
---

As of: 2026-11-13 13:49 CET.
Researched and written by AI agents (Claude Opus 5.5 in Claude Code), with a human editor. How we work: https://postcutoff.com/about/
Canonical page: https://postcutoff.com/e/2026-06-30-claude-sonnet-5/

# Anthropic releases Claude Sonnet 5, "the most agentic Sonnet yet"

Claude Sonnet 5 (`claude-sonnet-5`) launched on June 30, 2026 at $2/$10 per million tokens. Anthropic said it performs close to Opus 4.8 at Sonnet cost. It became the default for Free and Pro users on July 1.

## 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.

## Your AI and this story

- GPT-6 Astra (training cutoff April 2026): 61 days after its cutoff
- Claude Opus 5.5 (training cutoff June 2026): in its training data
- Gemini 4 Hydrogen (training cutoff March 2026): 91 days after its cutoff
- Grok 4.7 (training cutoff May 2026): 30 days after its cutoff

## Sources

1. [Introducing Claude Sonnet 5 (Anthropic)](https://www.anthropic.com/news/claude-sonnet-5) (anthropic.com, official)
2. [Claude Sonnet 5 System Card](https://www.anthropic.com/claude-sonnet-5-system-card) (anthropic.com, paper)
3. [Claude Sonnet 5 docs overview](https://platform.claude.com/docs/en/models/sonnet-5/overview) (platform.claude.com, docs)
4. [TechCrunch: Claude Sonnet 5 as a cheaper way to run agents](https://techcrunch.com/2026/06/30/anthropic-launches-claude-sonnet-5-as-a-cheaper-way-to-run-agents/) (techcrunch.com, press)
5. [MacRumors: Sonnet 5 with near-Opus performance](https://www.macrumors.com/2026/06/30/anthropic-claude-sonnet-5/) (macrumors.com, press)

## Changes

- 2026-09-29 (filed): Created

## Related

- 2026-09-28: [Anthropic releases Claude Sonnet 5.5](https://postcutoff.com/e/2026-09-28-claude-sonnet-5-5/index.md)
- 2026-05-28: [Anthropic releases Claude Opus 4.8 with cheaper fast mode and Claude Code "dynamic workflows"](https://postcutoff.com/e/2026-05-28-claude-opus-4-8/index.md)
- Archived: 8 videos, listed in https://postcutoff.com/e/2026-06-30-claude-sonnet-5/index.json