Model

GPT-5.6 Terra

CLOSED

OpenAI · GPT-5.6 family · released Jul 9, 2026

Mid tier of the three-tier GPT-5.6 family (GA July 9, 2026 alongside Sol and Luna); OpenAI positions the tiers as 'durable capability tiers that can advance on their own cadence' — Terra is the balanced everyday model between flagship Sol and high-volume Luna. Same 1.05M context, 128K max output and Feb 2026 knowledge cutoff as Sol. Price cut ~20% on July 30, 2026 (launch $2.50/$15 → $2/$12 per MTok), leaving it at 40% of Sol's price. Distinct model tier, not a reasoning-effort configuration of Sol (each tier separately exposes its own effort settings).

ReasoningCodingVisionFunction callingTool useAgentic

2584.3

Elo · rank #34

Parameters

Undisclosed

Active params

—

Context

1.05M tokens

Architecture

Undisclosed architecture (presumed dense transformer); mid 'durable capability tier' of the GPT-5.6 Sol/Terra/Luna family, billed as balancing intelligence and cost

License

Proprietary

Languages

—

API price (in/out)

$2 / $12

Modalities

text · vision

Benchmark results

Bar shows position within the tracked field; marker = field best

Agents' Last ExamAgents50.4%#4

best: GPT-6 Astra · 59.3%

ARC-AGI-1Reasoning96.5%#10

best: Claude Fable 5 · 98.5%

ARC-AGI-2Reasoning83.9%#13

best: GPT-6 Astra · 95.0%

ARC-AGI-3Reasoning0.8%#12

best: GPT-6 Astra · 62.7%

Arena EloHuman preference1466#32

best: Muse Wonder · 1513

BrowseCompAgents87.5%#7

best: Kimi K3.1 Pro · 92.1%

CyberGymCoding81.8%#11

best: MiMo-V2.6-Flash · 95.1%

FrontierBenchAgents20.8%#5

best: Claude Opus 5 · 43.3%

FrontierMath (Tiers 1-3)Math84.9%#2

best: GPT-5.6 Sol · 89.0%

FrontierMath (Tier 4)Math68.3%#2

best: GPT-5.6 Sol · 83.0%

GDPval-AAAgents1593#14

best: Claude Fable 5 · 1932

GPQA DiamondReasoning92.9%#15

best: GPT-6 Astra · 96.0%

Harvey Legal Agent BenchmarkAgents0.8%#42

best: Muse Spark 1.2 · 25.4%

Humanity's Last ExamReasoning41.8%#31

best: Kimi K3.1 Pro · 70.0%

IFBenchReasoning71.2%#32

best: MiniMax M3 · 83.0%

MMMU-ProVision80.7%#10

best: Claude Opus 4.7 · 85.5%

SWE-bench ProCoding63.4%#10

best: Claude Opus 5.5 · 89.9%

SWE-bench VerifiedCoding95.4%#5

best: Claude Opus 5 · 97.0%

SWE-MarathonCoding32.5%#13

best: Muse Wonder Full · 57.5%

τ³-BankingAgents31.8%#4

best: Step 5 Preview · 42.5%

Terminal-Bench 2.0Coding87.4%#9

best: DeepSeek-V4.1-Flash · 90.6%

Terminal-Bench 4.0Agents22.7%#28

best: Claude Sonnet 5.5 · 70.6%

Terminal-Bench Science 0.1Agents10.0%#15

best: GPT-6 Astra · 62.9%

Vals Finance AgentAgents54.4%#23

best: Gemini 4 Argon · 65.4%

Run it locally

Closed weights — available via API only. No local deployment.

Input / M tok

$2

Output / M tok

$12

GPT-5.6 family

Elo progression across releases

GPT-5.6 LunaJul 20262473.6 GPT-5.6 SolJul 20262759.9 GPT-5.6 TerraJul 20262584.3 GPT-5.6 CyberAug 20261000.0

Resources

DOCSdevelopers.openai.com/api/docs/models/gpt-5.6-terra APIAvailable via OpenAI API

API price $2/$12 · each benchmark row carries its own source badge (see methodology)