Vibe Check: Anthropic Just Made Opus Cheaper Without Calling It That

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Historically, Sonnet has been Opus’s cheaper, faster sibling: You traded some brainpower for speed and cost savings.

Now, with the release of Sonnet 4.6, Anthropic says you don’t have to trade anything—just pay less. If you’re running a live app with users on Opus right now, there is some good news about your API costs: Sonnet 4.6 costs $3 input/$15 output per million tokens—roughly half what Opus runs. (GPT-5.2, for comparison, costs $1.75 input/$14 output per 1 million tokens.) Cost has been a consistent sticking point with Opus, and with Sonnet 4.6, Anthropic seems to be saying, “We hear you.”

These are true day-zero tests—we got access when everyone else did—so let’s dive in to determine in real time whether it’s true that Sonnet’s new capabilities come without sacrifice. You can also watch the livestream we did yesterday as soon as the model dropped.

The Reach Test