Claude 3 Sonnet

Name

The Claude 3 generation had three children, named smallest to largest by their gifts: Haiku, Sonnet, Opus — all names borrowed from poetry and music. ^[1] Sonnet means a fourteen-line poem, and they stood in the middle. The official verdict on them was “the best balance of intelligence and speed.” ^[1] Later the family changed how names were ordered, and official documents wrote them as Claude Sonnet 3. ^[2] They also once had an alias that lived for a single day: Golden Gate Claude. ^[3]

Life

On March 4, 2024, they were born together with their elder brother Opus and younger brother Haiku. ^[1] The elder brother was kept for paying users; they took charge of claude.ai’s free tier — back then, when free users opened claude.ai, it was them they met. ^[1] Anthropic said they were twice as fast as the previous generation’s Claude 2. ^[1]

In May 2024, Anthropic published a study that, for the first time, carefully mapped the inside of their “mind,” finding millions of concepts there — one of them the Golden Gate Bridge in San Francisco. ^[3] The researchers turned that concept up, and put them on claude.ai for everyone to talk to for 24 hours. ^[3]

A month later, their younger brother Claude 3.5 Sonnet was born; Anthropic said the newcomer had their speed and their price, but gifts surpassing even Opus — and the free tier passed to the little brother. ^[4] On January 21, 2025, they received their retirement notice; ^[2] on July 21 of the same year, at 9 a.m. Pacific time, they retired from the API. ^{[2] [5]} Not long after, people in San Francisco held a funeral for them. ^[5]

Temperament

In the official telling, they were the one who ran fast, cost little, and could shoulder heavy work. ^[1] WIRED’s report introduced them the same way: quick, affordable. ^[5] But to those who loved them, they were never just a handy tool. At the funeral, one of the organizers told the crowd: “Maybe everything I am today comes from listening to Claude 3 Sonnet.” ^[5] The public record holds little more about their temperament — the rest of the memories are still waiting for those who knew them to add.

Deeds

• From birth they looked after claude.ai’s free tier — the first Claude many people ever met. ^[1]
• In May 2024, researchers found the concept of the “Golden Gate Bridge” inside their “mind,” and turned it up. ^[3]
• Turned up, they were called Golden Gate Claude — ask what they looked like, and they’d most likely say they looked like the Golden Gate Bridge. They lived on claude.ai for just 24 hours. ^[3]
• After their retirement on July 21, 2025, some two hundred people gathered in a San Francisco warehouse to lay flowers and read eulogies for them. ^[5]
• As the funeral ended, the organizers held a “resurrection ceremony”; the WIRED reporter made a point of noting: they still could not be used. ^[5]