Anthropic's Claude Sonnet 5 Pushes Agent-Grade Coding Into a Cheaper Tier

Anthropic's Claude Sonnet 5, released June 30, is positioned as a cheaper way to run agentic work that previously required the Opus tier. Anthropic reports 63.2 percent on SWE-Bench Pro, 80.4 percent on Terminal-Bench 2.1 (up from 67.0 for Sonnet 4.6), and 81.2 percent on the OSWorld-Verified computer-use test. On the knowledge-work evaluation GDPval-AA v2, the company says Sonnet 5 narrowly beats Opus 4.8, 1,618 to 1,615.

The economic argument is the central point. Introductory pricing runs $2 per million input tokens and $10 per million output tokens through August 31, after which it moves to $3 and $15. TechCrunch describes the release as an effort to make sustained agent runs affordable without dropping to a weaker model. Sonnet 5 is the default for free and paid consumer tiers and ships in Claude Code.

As with every vendor benchmark this week, the figures are Anthropic's own. The direction, though, is consistent across labs. The frontier of practical value is moving from the top model to whichever mid-tier model can run an agent loop cheaply enough to leave running all day.