OpenAI took a third off its flagship's output price — and gave the cut an expiry date

On 21 August 2026 OpenAI's API changelog recorded a new price for GPT-5.6 Sol, the top tier of its mid-2026 frontier line: $4 per million input tokens and $20 per million output tokens, against $5 and $30 at launch. That is 20 percent off input and 33 percent off output. The pricing table moves with it — cached input drops from $0.50 to $0.40, with cache writes listed at $5. The wording is the part worth reading twice. OpenAI does not call this a new list price; it calls it promotional pricing, „available at least through November 21, 2026”. That is three months of guaranteed cover. Nothing in the changelog or on the pricing page says what happens on 22 November, and a permanent rate and a promotion that may lapse are different things to build a budget on. The cut also changes the shape of the line. Terra is unchanged at $2 and $12 per million tokens, Luna at $0.20 and $1.20. Until this week, reaching for the flagship instead of the middle tier cost two and a half times as much on both input and output. On the new rates it costs twice as much on input and roughly 1.7 times as much on output — by our arithmetic from the producer's own table, the smallest premium the top tier has carried since the line launched on 9 July 2026. What did not move is the cliff at the top of the context window. Any request whose input exceeds 272,000 tokens is still billed at twice the input rate and one and a half times the output rate for the whole request, which now works out at $8 and $30 — the long-context band therefore costs the same per output token as short-context calls did a week ago. The discounted queues follow the new rate: batch and flex both list Sol at $2 and $10, Fast mode at $8 and $40. The Daybreak Blue alias, which points approved defenders at gpt-5.6-sol, is priced identically.