reasoning effort

GPT-6.1 Terra costs $1/$5 per million tokens, half of Sol, and scores 48 to Sol's 52 on Artificial Analysis. At max effort it uses twice the tokens, so run it at low or medium.

Claude Haiku 5.5 matches GPT-6 Luna at $0.10/$0.50 per million tokens and beats it on Anthropic's evals, but prompts over 100K tokens cost 5x and its tokenizer counts about 30% more tokens than Haiku 4.5. Short-prompt classification and routing get the big saving; compaction and long-context work get much less.

Claude Sonnet 5.5 lists at half Opus 5.5's token price, but Artificial Analysis measured it at $7.60 per task at max effort against $3.46 for Opus at xhigh for the same score. It saves money only at low and high effort, and five breaking changes sit behind the model-ID swap.

GPT-6 Sol costs $2/$10 per million tokens, half GPT-5.6 Sol's promo rate, permanently. But OpenAI's headline evals ran at xhigh or max effort, and only one carries a dollar cost per task.

Claude Opus 5.5 cuts per-token prices 20% and cache reads 60%, but forced tool_choice and disabled thinking now return HTTP 400, the default effort drops to medium, and the 40% saving compares different effort levels.

Grok 4.7's per-token price didn't move. Its per-task cost did: up 47% at matched effort on Artificial Analysis's index, down 10% on Cursor's own benchmark. Price it on your workload.