Is GPT-5.6 Terra a good deal?

As of Sep 23, 2026, GPT-5.6 Terra is dominated for Balanced on LMArena. GPT-5.6 Sol scores 8.9 higher and costs 11% less, with a covering envelope. 13 of 136 rated, priced standard models are undominated.

Inspect model evidence Compare differences & requirements

GPT-5.6 Sol is both better and cheaper than GPT-5.6 Terra: 8.9 points higher on LMArena and 11% less per million tokens, $0.50 cheaper at this mix.

GPT-5.6 Terra takes file, image, text, returns up to 128,000 tokens from a 1,050,000-token context, and is listed by 7 sellers.

Compared against 136 rated, priced models on this lens: 1 model dominates it and gives up nothing, 5 more dominate it but give something up. GPT-5.6 Terra scores 1446.2 at $4.50 per million tokens for this mix.

Envelope-safe replacements

Each row scores at least as high, costs no more, and covers this model’s context, output, modalities, tools, and reasoning. A cheaper narrower model is not listed here.

Model	LMArena	Effective $/M	You save
GPT-5.6 Sol	1455.1 +8.9	$4.00/M	11%

Higher score, lower price, named losses

Not a drop-in. The loss is why these are not a recommendation.

Model	LMArena	Effective $/M	You give up
Gemini 3.8 Flash	1494.7	$1.50/M	context, max output
Gemini 3.7 Flash	1490.5	$1.50/M	context, max output
Muse Spark 1.3	1489.7	$2.00/M	context
Muse Spark 1.1	1480.2	$2.00/M	context
Gemini 3.1 Pro Preview	1480.1	$4.50/M	context, max output

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