GPT-5.6 Terra
Restricted
The capable, lower-cost tier of OpenAI's GPT-5.6 family, available in limited preview through the OpenAI API and Codex for approved organizations.
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Notes
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Context
1.1M
Weights
Closed
API only
Input
$2
/1M tok
Output
$12
/1M tok
Cache read
$0.20
0.10x input
Cache write
$2.50
1.25x input
Price & speed via Artificial Analysis · ranked across tracked models · caching via OpenRouter
| Reasoning effort | Index | Speed |
|---|---|---|
| max | 42.1 | 99 t/s |
| xhigh | 38.0 | 85 t/s |
| high | 34.2 | 88 t/s |
| medium | 30.1 | 87 t/s |
| low | 27.5 | 84 t/s |
| Non-reasoning | 20.8 | 91 t/s |
Intelligence Index per reasoning-effort setting, via Artificial Analysis · pricing identical across tiers
Reported on 24 evals across 13 domains - best 92.5% on GPQA Diamond · #20 of 511
Reported eval scores
24IFBench71.2
GPQA Diamond92.5
SciCode44.6
TaxEval v276.2
CorpFin v265.3
MortgageTax67.3
Vals Index53.1
EQ-Bench 41234