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Ranked #4 on Hacker News with 16 points and 7 comments.

GPT-5.6 Sol is the frontier model in the GPT-5.6 family. It roughly corresponds to the unsuffixed model tier used in earlier GPT-5 families. The gpt-5.6 alias routes requests to GPT-5.6 Sol. Reasoning.effort supports: none, low, medium (default), high, xhigh, and max.

GPT-5.6 Sol costs $4 per million input tokens and $20 per million output tokens, a 20% reduction in input pricing and a 33% reduction in output pricing. GPT-5.6 Sol’s promotional pricing is available at least through November 21, 2026.

Prompts with >272K input tokens are priced at 2x input and 1.5x output for the full request.

Cache writes are billed at 1.25x the uncached input token rate.