Truth Check/25 September 2026

“Claude Opus 5.5 costs 40% less to run than Opus 5”

The claim as it travelled: Anthropic, 22 Sept 2026 - at default settings on typical workloads.

Anthropic's page says 40% 'at default settings on typical workloads', netting fewer tokens per task with the 20% per-token cut; the claim carries that qualifier.

Checked Against

anthropic.com ↗Primary

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Anthropic and OpenAI cut their frontier prices on the same day - the 40 and the 50 are the sellers' numbers

Opus 5.5 is $4 in and $20 out; GPT-6 Sol is $2 and $10. Anthropic's 40% is a workload figure; OpenAI's 50% is against a promotional price.

Every claim we have checked, in the Ledger.