Claude Sonnet 4.6 is the smaller, cheaper tier of Anthropic’s Claude 4.6 generation, released after the larger Claude Opus 4.6. In this corpus it enters as the cheap model that beat the expensive one, claiming 1633 Elo on GDPval-AA and 63.3% on Finance Agent v1.1, a datapoint for the deflating price of reasoning.
AISystem
Claude Sonnet 4.6
Anthropic's mid-tier model of February 2026, which took the lead on GDPval-AA and Finance Agent v1.1 ahead of its own larger sibling Opus 4.6 at a fraction of the cost.
Sources
Attribution and reporting linked by this record; links do not imply independent verification.
- Welcome to February 18, 2026 (theinnermostloop.substack.com)
Development timeline
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