Summary
On August 11, 2026 Anthropic cancelled a previously scheduled price increase for Claude Sonnet 5. The $2 per million input / $10 per million output token rate — originally framed as introductory pricing through August 31, 2026 — becomes the standard price, and the planned September 1 move to $3/$15 will not take effect.
What changed
Anthropic scrapped the scheduled September 1, 2026 increase of Claude Sonnet 5 from $2/$10 to $3/$15 per million input/output tokens, making the lower introductory rate permanent.
Why it matters
Holding a mid-tier workhorse model at introductory pricing signals that competitive pressure — not cost — now sets frontier-lab API prices, protecting Anthropic's position against cheaper rivals as agent workloads make per-token cost a primary buying factor. For builders it removes a looming cost step-up on a heavily used model.
Evidence excerpt
The $2/$10 introductory pricing for Claude Sonnet 5, set to run through August 31, 2026, is now standard; "the previously scheduled increase to $3/$15 per million input/output tokens on September 1, 2026 will not occur."