Anthropic Makes Sonnet 5 the Default in Claude Code

Anthropic set Claude Sonnet 5 as the default model in Claude Code, shipping the change in version 2.1.197 with a native 1M-token context window. Anthropic says it is the most agentic Sonnet yet, with measurably lower rates of undesirable behavior than Sonnet 4.6 in agentic settings. For teams building autonomous agents, that reliability record matters as much as the token count.

As of July 2, Sonnet 5 is the default model on Free and Pro plans, and available to Max, Team, and Enterprise plans.

Pricing carries an introductory discount: $2 per million input tokens and $10 per million output tokens through August 31, 2026. After that the rate rises to $3 and $15.

What to watch

The introductory pricing is the real signal here: a $2/$10 rate that jumps 50% to $3/$15 after August 31. Watch whether usage holds once the discount ends. If it doesn't, the low rate was there to pull developers off Sonnet 4.6 before the real price kicks in. The August 31 deadline gives builders a firm window to test Sonnet 5 at the lower rate before it goes away.