Head-to-head comparison

GPT-5.6 Terra vs. Grok 4.6

Compare published benchmark results from matching versions and cohorts, API pricing, and technical specifications. Any documented test setup differences remain visible.

shared result series: 45
distinct benchmarks: 23
latest retrieval: 2026-09-04

First modelSecond model

Specifications

General specifications

Release date, availability, context window, architecture, and published parameter counts at a glance. Undisclosed details remain marked as unavailable.

Specifications for GPT-5.6 Terra and Grok 4.6
Attribute	GPT-5.6 Terra	Grok 4.6
Provider	OpenAI	xAI
Released	Jun 26, 2026	Aug 12, 2026
Availability	Active	Active
Model type	Proprietary	Proprietary
Parameters	Not published	Not published
Architecture	Not published	Not published
Context window	1,050,000 tokens	500,000 tokens
Knowledge cutoff	February 16, 2026	February 1, 2026
Technical sources	Model, Context, Knowledge cutoff	Model

Pricing

API pricing compared

The table compares official standard API rates per 1M tokens, including published cache pricing. Batch, fast, priority, regional surcharges, tool calls, and cloud platform pricing are excluded.

API pricing for GPT-5.6 Terra and Grok 4.6
Price type	GPT-5.6 Terra	Grok 4.6
API input	$2 ≤272K / $4 >272K	$2 ≤200K / $4 >200K
API output	$12 ≤272K / $18 >272K	$6 ≤200K / $12 >200K
Cache read	$0.2 ≤272K / $0.4 >272K	$0.5 ≤200K / $1 >200K
Cache write (5 min.)	$2.5 ≤272K / $5 >272K	Not listed
Cache write (1 hr.)	Not listed	Not listed
Price verified	08/11/2026 Source	08/16/2026 Source

GPT-5.6 TerraGrok 4.6

API inputUSD per 1M tokens, base tier

GPT-5.6 Terra$2

Grok 4.6$2

API outputUSD per 1M tokens, base tier

GPT-5.6 Terra$12

Grok 4.6$6

Cache readUSD per 1M tokens, base tier

GPT-5.6 Terra$0.2

Grok 4.6$0.5

Key to the marks:better valuebetter, but not conclusivetie

Pricing by provider

Direct developer pricing and provider endpoint tariffs routed through OpenRouter are listed separately. Prices are in USD per 1M tokens. Context-dependent direct tiers plus regional, Flex, Priority, and other OpenRouter tariffs remain individually identifiable.

Provider pricing for GPT-5.6 Terra and Grok 4.6
Model	Provider	Purchase route and tariff	Input per 1M tokens	Output per 1M tokens	Source
GPT-5.6 Terra	OpenAI	Direct from developerUp to 272,000 context tokens	$2	$12	Source08/11/2026
	OpenAI	Direct from developerAbove 272,000 context tokens	$4	$18	Source08/11/2026
	Amazon Bedrock	Via OpenRouteramazon-bedrock/us-east-1	$2.2	$13.2	Source09/06/2026
	Azure	Via OpenRouterazure	$2	$12	Source09/06/2026
	Azure	Via OpenRouterazure/eu	$2.2	$13.2	Source09/06/2026
	Azure	Via OpenRouterazure/us	$2.2	$13.2	Source09/06/2026
	OpenAI	Via OpenRouteropenai	$2	$12	Source09/06/2026
	OpenAI	Via OpenRouteropenai/fast	$4	$24	Source09/06/2026
	OpenAI	Via OpenRouteropenai/flex	Lowest listed price: $1	Lowest listed price: $6	Source09/06/2026
Grok 4.6	xAI	Direct from developerUp to 200,000 context tokens	Lowest listed price: $2	Lowest listed price: $6	Source08/16/2026
	xAI	Direct from developerAbove 200,000 context tokens	$4	$12	Source08/16/2026
	Amazon Bedrock	Via OpenRouteramazon-bedrock/us-west-2	$2.2	$6.6	Source09/06/2026
	xAI	Via OpenRouterxai	Lowest listed price: $2	Lowest listed price: $6	Source09/06/2026
	xAI	Via OpenRouterxai/priority	$4	$12	Source09/06/2026
	xAI	Via OpenRouterxai/zdr	Lowest listed price: $2	Lowest listed price: $6	Source09/06/2026
	xAI	Via OpenRouterxai/zdr/priority	$4	$12	Source09/06/2026

Performance

Shared benchmarks

Only published results with the same benchmark version, task, metric, and comparison cohort are paired. Different reasoning levels, agents, harnesses, or output limits appear directly in the table.

Capability profile from matched benchmarks

Each axis averages directly matched benchmark families. A value of 100 means the stronger value within this pair, not a universal quality score.

GPT-5.6 Terra

Grok 4.6

Coding: 98.8 / 98.3 (4 benchmark families)

Reasoning: 96 / 100 (1 benchmark family)

Mathematics: 100 / 68.9 (1 benchmark family)

Knowledge: 96.9 / 100 (1 benchmark family)

Finance: 99.7 / 96.4 (5 benchmark families)

Legal: 63.3 / 100 (3 benchmark families)

Agentic tasks: 99.5 / 97.3 (2 benchmark families)

Productivity: 93.3 / 100 (1 benchmark family)

22 matched rows from 22 benchmark families were considered. The radar shows 8 of 11 comparable categories.

GPT-5.6 TerraGrok 4.6

Code MigrationOverall. Higher is better. No documented setup difference

GPT-5.6 Terra47.804 %

Grok 4.644.572 %

CorpFin v2Overall. Higher is better. No documented setup difference

GPT-5.6 Terra65.307 %

Grok 4.666.161 %

EMBOverall. Higher is better. No documented setup difference

GPT-5.6 Terra66.205 %

Grok 4.662.727 %

Finance Agent (v2)Overall. Higher is better. No documented setup difference

GPT-5.6 Terra54.436 %

Grok 4.653.682 %

GPQA DiamondOverall. Higher is better. No documented setup difference

GPT-5.6 Terra90.909 %

Grok 4.694.697 %

Harvey's Legal Agent BenchmarkOverall · Task fully resolved. Higher is better. No documented setup difference

GPT-5.6 Terra0.833 %

Grok 4.615.833 %

Legal Research BenchOverall · All-pass. Higher is better. No documented setup difference

GPT-5.6 Terra41.346 %

Grok 4.648.077 %

LegalBenchOverall. Higher is better. No documented setup difference

GPT-5.6 Terra85.105 %

Grok 4.686.307 %

LiveCodeBench v6Overall. Higher is better. No documented setup difference

GPT-5.6 Terra85.93 %

Grok 4.688.224 %

LMArena Text, Style ControlOverall. Higher is better. Test setup not documented as identical

GPT-5.6 Terra1,466.233

Grok 4.61,461.115

MedCodeOverall. Higher is better. No documented setup difference

GPT-5.6 Terra43.414 %

Grok 4.644.712 %

MedScribeOverall. Higher is better. No documented setup difference

GPT-5.6 Terra82.869 %

Grok 4.686.534 %

Key to the marks:better valuebetter, but not conclusivetie

Benchmark scores for GPT-5.6 Terra and Grok 4.6
Benchmark and task	GPT-5.6 Terra	Grok 4.6	Source
Code MigrationOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner47.804 %	44.572 %	Vals AI Source details Data as of: 09/03/2026
CorpFin v2Overall Test details No documented difference in the test setupVersion: 2Metric: accuracyScoring: Higher is better	65.307 %	Winner66.161 %	Vals AI Source details Data as of: 08/12/2026
EMBOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner66.205 %	62.727 %	Vals AI Source details Data as of: 09/03/2026
Finance Agent (v2)Overall Test details No documented difference in the test setupVersion: 2Metric: accuracyScoring: Higher is better	Winner54.436 %	53.682 %	Vals AI Source details Data as of: 09/03/2026
GPQA DiamondOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	90.909 %	Winner94.697 %	Vals AI Source details Data as of: 09/01/2026
Harvey's Legal Agent BenchmarkOverall · Task fully resolved Test details No documented difference in the test setupVersion: 1Metric: task resolution rateScoring: Higher is better	0.833 %	Winner15.833 %	Vals AI Source details Data as of: 09/03/2026
Legal Research BenchOverall · All-pass Test details No documented difference in the test setupVersion: 1Metric: all-pass rateScoring: Higher is better	41.346 %	Winner48.077 %	Vals AI Source details Data as of: 09/03/2026
LegalBenchOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	85.105 %	Winner86.307 %	Vals AI Source details Data as of: 09/01/2026
LiveCodeBench v6Overall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	85.93 %	Winner88.224 %	Vals AI Source details Data as of: 09/01/2026
LMArena Text, Style ControlOverall Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterGPT-5.6 Terra: Snapshot: gpt-5.6-terra-xhigh, Reasoning: xhigh, Harness: Arena text, style control Grok 4.6: Snapshot: grok-4.6-high, Reasoning: high, Harness: Arena text, style controlGPT-5.6 Terra: Style-controlled Arena rating from 23,942 anonymous pairwise votes.Grok 4.6: Style-controlled Arena rating from 3,453 anonymous pairwise votes.	Higher measured value1,466.233 95% confidence interval: ±5.062The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	1,461.115 95% confidence interval: ±10.144The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	LMArena Source details Data as of: 09/01/2026
MedCodeOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	43.414 %	Winner44.712 %	Vals AI Source details Data as of: 09/03/2026
MedScribeOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	82.869 %	Winner86.534 %	Vals AI Source details Data as of: 09/03/2026
MMLU-ProOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	86.659 %	Winner89.4 %	Vals AI Source details Data as of: 09/01/2026
MortgageTaxOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner67.329 %	64.189 %	Vals AI Source details Data as of: 09/01/2026
ProofBenchOverall Test details No documented difference in the test setupVersion: 1.1Metric: accuracyScoring: Higher is better	Winner74 %	51 %	Vals AI Source details Data as of: 09/01/2026
Public Benefits Bench v1.1Overall Test details No documented difference in the test setupVersion: 1.1Metric: accuracyScoring: Higher is better	62.382 %	Winner66.847 %	Vals AI Source details Data as of: 09/01/2026
SAGEOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner47.003 %	28.9 %	Vals AI Source details Data as of: 09/03/2026
SkillsBenchOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is betterSettings: Harness: OpenHands	Winner58.895 %	55.766 %	Vals AI Source details Data as of: 09/01/2026
SWE-bench VerifiedOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	95.4 %	Winner95.6 %	Vals AI Source details Data as of: 09/01/2026
TaxEval v2Overall Test details No documented difference in the test setupVersion: 2Metric: accuracyScoring: Higher is better	Winner76.166 %	71.096 %	Vals AI Source details Data as of: 09/01/2026
Terminal-Bench 2.1Overall Test details No documented difference in the test setupVersion: 2.1Metric: accuracyScoring: Higher is better	77.528 %	Winner78.277 %	Vals AI Source details Data as of: 09/03/2026
Vals IndexOverall Test details No documented difference in the test setupVersion: 2Metric: weighted index scoreScoring: Higher is better	Winner59.588 %	59.167 %	Vals AI Source details Data as of: 09/03/2026
Vibe Code Bench v1.1Overall Test details No documented difference in the test setupVersion: 1.1Metric: accuracyScoring: Higher is betterSettings: Harness: OpenHands	74.594 %	Winner76.239 %	Vals AI Source details Data as of: 09/03/2026
LMArena Text, Style ControlBusiness, management and finance Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterGPT-5.6 Terra: Snapshot: gpt-5.6-terra-xhigh, Reasoning: xhigh, Harness: Arena text, style control Grok 4.6: Snapshot: grok-4.6-high, Reasoning: high, Harness: Arena text, style controlGPT-5.6 Terra: Style-controlled Arena rating from 4,559 anonymous pairwise votes.Grok 4.6: Style-controlled Arena rating from 705 anonymous pairwise votes.	1,467.133 95% confidence interval: ±9.403The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	Higher measured value1,467.318 95% confidence interval: ±22.146The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	LMArena Source details Data as of: 09/01/2026
LMArena Text, Style ControlChinese Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterGPT-5.6 Terra: Snapshot: gpt-5.6-terra-xhigh, Reasoning: xhigh, Harness: Arena text, style control Grok 4.6: Snapshot: grok-4.6-high, Reasoning: high, Harness: Arena text, style controlGPT-5.6 Terra: Style-controlled Arena rating from 1,627 anonymous pairwise votes.Grok 4.6: Style-controlled Arena rating from 291 anonymous pairwise votes.	1,518.544 95% confidence interval: ±15.369The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	Higher measured value1,538.386 95% confidence interval: ±33.69The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	LMArena Source details Data as of: 09/01/2026
LMArena Text, Style ControlCoding Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterGPT-5.6 Terra: Snapshot: gpt-5.6-terra-xhigh, Reasoning: xhigh, Harness: Arena text, style control Grok 4.6: Snapshot: grok-4.6-high, Reasoning: high, Harness: Arena text, style controlGPT-5.6 Terra: Style-controlled Arena rating from 6,608 anonymous pairwise votes.Grok 4.6: Style-controlled Arena rating from 838 anonymous pairwise votes.	Higher measured value1,518.601 95% confidence interval: ±8.056The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	1,510.751 95% confidence interval: ±20.826The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	LMArena Source details Data as of: 09/01/2026
LMArena Text, Style ControlCreative writing Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterGPT-5.6 Terra: Snapshot: gpt-5.6-terra-xhigh, Reasoning: xhigh, Harness: Arena text, style control Grok 4.6: Snapshot: grok-4.6-high, Reasoning: high, Harness: Arena text, style controlGPT-5.6 Terra: Style-controlled Arena rating from 4,918 anonymous pairwise votes.Grok 4.6: Style-controlled Arena rating from 651 anonymous pairwise votes.	1,426.255 95% confidence interval: ±9.432The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	Higher measured value1,458.096 95% confidence interval: ±23.926The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	LMArena Source details Data as of: 09/01/2026
LMArena Text, Style ControlEnglish Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterGPT-5.6 Terra: Snapshot: gpt-5.6-terra-xhigh, Reasoning: xhigh, Harness: Arena text, style control Grok 4.6: Snapshot: grok-4.6-high, Reasoning: high, Harness: Arena text, style controlGPT-5.6 Terra: Style-controlled Arena rating from 9,928 anonymous pairwise votes.Grok 4.6: Style-controlled Arena rating from 1,434 anonymous pairwise votes.	Higher measured value1,470.27 95% confidence interval: ±6.803The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	1,459.46 95% confidence interval: ±15.407The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	LMArena Source details Data as of: 09/01/2026
LMArena Text, Style ControlEntertainment, sports and media Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterGPT-5.6 Terra: Snapshot: gpt-5.6-terra-xhigh, Reasoning: xhigh, Harness: Arena text, style control Grok 4.6: Snapshot: grok-4.6-high, Reasoning: high, Harness: Arena text, style controlGPT-5.6 Terra: Style-controlled Arena rating from 6,035 anonymous pairwise votes.Grok 4.6: Style-controlled Arena rating from 777 anonymous pairwise votes.	1,434.209 95% confidence interval: ±8.525The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	Higher measured value1,443.149 95% confidence interval: ±21.821The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	LMArena Source details Data as of: 09/01/2026
LMArena Text, Style ControlExcluding ties Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterGPT-5.6 Terra: Snapshot: gpt-5.6-terra-xhigh, Reasoning: xhigh, Harness: Arena text, style control Grok 4.6: Snapshot: grok-4.6-high, Reasoning: high, Harness: Arena text, style controlGPT-5.6 Terra: Style-controlled Arena rating from 17,956 anonymous pairwise votes.Grok 4.6: Style-controlled Arena rating from 2,522 anonymous pairwise votes.	Higher measured value1,473.839 95% confidence interval: ±6.594The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	1,465.128 95% confidence interval: ±14.002The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	LMArena Source details Data as of: 09/01/2026
LMArena Text, Style ControlExpert prompts Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterGPT-5.6 Terra: Snapshot: gpt-5.6-terra-xhigh, Reasoning: xhigh, Harness: Arena text, style control Grok 4.6: Snapshot: grok-4.6-high, Reasoning: high, Harness: Arena text, style controlGPT-5.6 Terra: Style-controlled Arena rating from 2,711 anonymous pairwise votes.Grok 4.6: Style-controlled Arena rating from 401 anonymous pairwise votes.	Higher measured value1,506.472 95% confidence interval: ±11.876The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	1,479.844 95% confidence interval: ±28.841The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	LMArena Source details Data as of: 09/01/2026
LMArena Text, Style ControlHard prompts Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterGPT-5.6 Terra: Snapshot: gpt-5.6-terra-xhigh, Reasoning: xhigh, Harness: Arena text, style control Grok 4.6: Snapshot: grok-4.6-high, Reasoning: high, Harness: Arena text, style controlGPT-5.6 Terra: Style-controlled Arena rating from 15,816 anonymous pairwise votes.Grok 4.6: Style-controlled Arena rating from 2,312 anonymous pairwise votes.	Higher measured value1,490.153 95% confidence interval: ±5.922The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	1,484.219 95% confidence interval: ±12.5The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	LMArena Source details Data as of: 09/01/2026
LMArena Text, Style ControlHard prompts, English Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterGPT-5.6 Terra: Snapshot: gpt-5.6-terra-xhigh, Reasoning: xhigh, Harness: Arena text, style control Grok 4.6: Snapshot: grok-4.6-high, Reasoning: high, Harness: Arena text, style controlGPT-5.6 Terra: Style-controlled Arena rating from 6,463 anonymous pairwise votes.Grok 4.6: Style-controlled Arena rating from 927 anonymous pairwise votes.	Higher measured value1,488.472 95% confidence interval: ±8.092The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	1,475.235 95% confidence interval: ±19.394The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	LMArena Source details Data as of: 09/01/2026
LMArena Text, Style ControlInstruction following Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterGPT-5.6 Terra: Snapshot: gpt-5.6-terra-xhigh, Reasoning: xhigh, Harness: Arena text, style control Grok 4.6: Snapshot: grok-4.6-high, Reasoning: high, Harness: Arena text, style controlGPT-5.6 Terra: Style-controlled Arena rating from 8,484 anonymous pairwise votes.Grok 4.6: Style-controlled Arena rating from 1,223 anonymous pairwise votes.	Higher measured value1,462.94 95% confidence interval: ±7.323The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	1,458.276 95% confidence interval: ±17.043The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	LMArena Source details Data as of: 09/01/2026
LMArena Text, Style ControlLegal and government Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterGPT-5.6 Terra: Snapshot: gpt-5.6-terra-xhigh, Reasoning: xhigh, Harness: Arena text, style control Grok 4.6: Snapshot: grok-4.6-high, Reasoning: high, Harness: Arena text, style controlGPT-5.6 Terra: Style-controlled Arena rating from 2,012 anonymous pairwise votes.Grok 4.6: Style-controlled Arena rating from 284 anonymous pairwise votes.	Higher measured value1,482.71 95% confidence interval: ±14.031The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	1,475.664 95% confidence interval: ±33.128The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	LMArena Source details Data as of: 09/01/2026
LMArena Text, Style ControlLife, physical and social science Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterGPT-5.6 Terra: Snapshot: gpt-5.6-terra-xhigh, Reasoning: xhigh, Harness: Arena text, style control Grok 4.6: Snapshot: grok-4.6-high, Reasoning: high, Harness: Arena text, style controlGPT-5.6 Terra: Style-controlled Arena rating from 3,853 anonymous pairwise votes.Grok 4.6: Style-controlled Arena rating from 512 anonymous pairwise votes.	1,471.733 95% confidence interval: ±10.065The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	Higher measured value1,492.359 95% confidence interval: ±25.684The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	LMArena Source details Data as of: 09/01/2026
LMArena Text, Style ControlLonger queries Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterGPT-5.6 Terra: Snapshot: gpt-5.6-terra-xhigh, Reasoning: xhigh, Harness: Arena text, style control Grok 4.6: Snapshot: grok-4.6-high, Reasoning: high, Harness: Arena text, style controlGPT-5.6 Terra: Style-controlled Arena rating from 11,195 anonymous pairwise votes.Grok 4.6: Style-controlled Arena rating from 1,609 anonymous pairwise votes.	1,469.496 95% confidence interval: ±6.879The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	Higher measured value1,478.218 95% confidence interval: ±15.132The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	LMArena Source details Data as of: 09/01/2026
LMArena Text, Style ControlMath Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterGPT-5.6 Terra: Snapshot: gpt-5.6-terra-xhigh, Reasoning: xhigh, Harness: Arena text, style control Grok 4.6: Snapshot: grok-4.6-high, Reasoning: high, Harness: Arena text, style controlGPT-5.6 Terra: Style-controlled Arena rating from 1,011 anonymous pairwise votes.Grok 4.6: Style-controlled Arena rating from 216 anonymous pairwise votes.	Higher measured value1,481.765 95% confidence interval: ±18.298The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	1,426.012 95% confidence interval: ±40.021The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	LMArena Source details Data as of: 09/01/2026
LMArena Text, Style ControlMathematical professions Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterGPT-5.6 Terra: Snapshot: gpt-5.6-terra-xhigh, Reasoning: xhigh, Harness: Arena text, style control Grok 4.6: Snapshot: grok-4.6-high, Reasoning: high, Harness: Arena text, style controlGPT-5.6 Terra: Style-controlled Arena rating from 1,255 anonymous pairwise votes.Grok 4.6: Style-controlled Arena rating from 212 anonymous pairwise votes.	Higher measured value1,493.251 95% confidence interval: ±16.992The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	1,456.037 95% confidence interval: ±39.211The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	LMArena Source details Data as of: 09/01/2026
LMArena Text, Style ControlMedicine and healthcare Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterGPT-5.6 Terra: Snapshot: gpt-5.6-terra-xhigh, Reasoning: xhigh, Harness: Arena text, style control Grok 4.6: Snapshot: grok-4.6-high, Reasoning: high, Harness: Arena text, style controlGPT-5.6 Terra: Style-controlled Arena rating from 1,777 anonymous pairwise votes.Grok 4.6: Style-controlled Arena rating from 225 anonymous pairwise votes.	1,457.251 95% confidence interval: ±14.871The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	Higher measured value1,460.477 95% confidence interval: ±37.871The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	LMArena Source details Data as of: 09/01/2026
LMArena Text, Style ControlMulti-turn Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterGPT-5.6 Terra: Snapshot: gpt-5.6-terra-xhigh, Reasoning: xhigh, Harness: Arena text, style control Grok 4.6: Snapshot: grok-4.6-high, Reasoning: high, Harness: Arena text, style controlGPT-5.6 Terra: Style-controlled Arena rating from 4,011 anonymous pairwise votes.Grok 4.6: Style-controlled Arena rating from 569 anonymous pairwise votes.	Higher measured value1,472.964 95% confidence interval: ±9.983The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	1,446.12 95% confidence interval: ±25.079The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	LMArena Source details Data as of: 09/01/2026
LMArena Text, Style ControlNon-English Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterGPT-5.6 Terra: Snapshot: gpt-5.6-terra-xhigh, Reasoning: xhigh, Harness: Arena text, style control Grok 4.6: Snapshot: grok-4.6-high, Reasoning: high, Harness: Arena text, style controlGPT-5.6 Terra: Style-controlled Arena rating from 14,012 anonymous pairwise votes.Grok 4.6: Style-controlled Arena rating from 2,019 anonymous pairwise votes.	Higher measured value1,457.182 95% confidence interval: ±6.084The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	1,456.123 95% confidence interval: ±13.128The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	LMArena Source details Data as of: 09/01/2026
LMArena Text, Style ControlRussian Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterGPT-5.6 Terra: Snapshot: gpt-5.6-terra-xhigh, Reasoning: xhigh, Harness: Arena text, style control Grok 4.6: Snapshot: grok-4.6-high, Reasoning: high, Harness: Arena text, style controlGPT-5.6 Terra: Style-controlled Arena rating from 2,447 anonymous pairwise votes.Grok 4.6: Style-controlled Arena rating from 413 anonymous pairwise votes.	Higher measured value1,468.509 95% confidence interval: ±12.279The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	1,446.297 95% confidence interval: ±28.9The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	LMArena Source details Data as of: 09/01/2026
LMArena Text, Style ControlSoftware and IT services Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterGPT-5.6 Terra: Snapshot: gpt-5.6-terra-xhigh, Reasoning: xhigh, Harness: Arena text, style control Grok 4.6: Snapshot: grok-4.6-high, Reasoning: high, Harness: Arena text, style controlGPT-5.6 Terra: Style-controlled Arena rating from 9,456 anonymous pairwise votes.Grok 4.6: Style-controlled Arena rating from 1,379 anonymous pairwise votes.	Higher measured value1,504.665 95% confidence interval: ±6.999The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	1,503.685 95% confidence interval: ±16.15The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	LMArena Source details Data as of: 09/01/2026
LMArena Text, Style ControlWriting, literature and language Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterGPT-5.6 Terra: Snapshot: gpt-5.6-terra-xhigh, Reasoning: xhigh, Harness: Arena text, style control Grok 4.6: Snapshot: grok-4.6-high, Reasoning: high, Harness: Arena text, style controlGPT-5.6 Terra: Style-controlled Arena rating from 6,463 anonymous pairwise votes.Grok 4.6: Style-controlled Arena rating from 921 anonymous pairwise votes.	Higher measured value1,449.136 95% confidence interval: ±8.227The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	1,445.223 95% confidence interval: ±19.746The Arena score measures human preference rather than a fixed capability test. The confidence interval and model configuration are part of the result.	LMArena Source details Data as of: 09/01/2026
Key to the marks:better valuebetter, but not conclusivetie

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