Head-to-head comparison

Claude Opus 4.5 vs. GPT-5.6 Terra

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

shared result series: 49
distinct benchmark metrics: 14
latest retrieval: 2026-10-19

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 Claude Opus 4.5 and GPT-5.6 Terra
Attribute	Claude Opus 4.5	GPT-5.6 Terra
Provider	Anthropic	OpenAI
Released	Nov 2025	Jul 9, 2026
Availability	Active	Active
Model type	Proprietary	Proprietary
Parameters	Not published	Not published
Architecture	Not published	Not published
Context window	200,000 tokens	1,050,000 tokens
Knowledge cutoff	May 2025	February 16, 2026
Technical sources	Model, Context	Model, Context, Knowledge cutoff

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 Claude Opus 4.5 and GPT-5.6 Terra
Price type	Claude Opus 4.5	GPT-5.6 Terra
API input	$5	$2 ≤272K / $4 >272K
API output	$25	$12 ≤272K / $18 >272K
Cache read	$0.5	$0.2 ≤272K / $0.4 >272K
Cache write (5 min.)	$6.25	$2.5 ≤272K / $5 >272K
Cache write (1 hr.)	$10	Not listed
Price verified	09/22/2026 Source	09/22/2026 Source

Claude Opus 4.5GPT-5.6 Terra

API inputUSD per 1M tokens, base tier

Claude Opus 4.5$5

GPT-5.6 Terra$2

API outputUSD per 1M tokens, base tier

Claude Opus 4.5$25

GPT-5.6 Terra$12

Cache readUSD per 1M tokens, base tier

Claude Opus 4.5$0.5

GPT-5.6 Terra$0.2

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 Claude Opus 4.5 and GPT-5.6 Terra
Model	Provider	Purchase route and tariff	Input per 1M tokens	Output per 1M tokens	Source
Claude Opus 4.5	Anthropic	Direct from developerStandard API	Lowest listed price: $5	Lowest listed price: $25	Source09/22/2026
	Amazon Bedrock	Via OpenRouteramazon-bedrock	Lowest listed price: $5	Lowest listed price: $25	Source10/26/2026
	Amazon Bedrock	Via OpenRouteramazon-bedrock/eu-west-1	$5.5	$27.5	Source10/26/2026
	Anthropic	Via OpenRouteranthropic	Lowest listed price: $5	Lowest listed price: $25	Source10/26/2026
	Azure	Via OpenRouterazure/global	Lowest listed price: $5	Lowest listed price: $25	Source10/26/2026
	Claude Platform on AWS	Via OpenRouterclaude-on-aws	Lowest listed price: $5	Lowest listed price: $25	Source10/26/2026
	Google	Via OpenRoutergoogle-vertex/global	Lowest listed price: $5	Lowest listed price: $25	Source10/26/2026
GPT-5.6 Terra	OpenAI	Direct from developerUp to 272,000 context tokens	$2	$12	Source09/22/2026
	OpenAI	Direct from developerAbove 272,000 context tokens	$4	$18	Source09/22/2026
	Amazon Bedrock	Via OpenRouteramazon-bedrock/us-east-1	$2.2	$13.2	Source10/26/2026
	Azure	Via OpenRouterazure	$2	$12	Source10/26/2026
	Azure	Via OpenRouterazure/eu	$2.2	$13.2	Source10/26/2026
	Azure	Via OpenRouterazure/us	$2.2	$13.2	Source10/26/2026
	OpenAI	Via OpenRouteropenai	$2	$12	Source10/26/2026
	OpenAI	Via OpenRouteropenai/fast	$4	$24	Source10/26/2026
	OpenAI	Via OpenRouteropenai/flex	Lowest listed price: $1	Lowest listed price: $6	Source10/26/2026

Benchmark index

Benchmark index compared

The index combines independent benchmarks on a scale from 0 to 100. A lead only counts when a model comes first in at least 95% of 200 recalculations with randomly redrawn test families. Otherwise both count as level.

Open the AI leaderboard

Claude Opus 4.5

Overall index

12.1

GPT-5.6 Terra

Overall index

52.1

GPT-5.6 Terra leads in 9 of 9 shared areas.

Area	Claude Opus 4.5	GPT-5.6 Terra
Coding	8.1	61.3
Reasoning	7.0	56.6
Knowledge	10.8	29.3
Agents	12.3	61.8
Finance	19.8	60.4
Legal	15.3	41.4
Health	19.6	40.3
Multimodal	10.4	47.7
Education	17.1	56.5

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.

Not enough directly matched categories for a reliable radar

Only 2 of at least 5 categories have comparable, direct model measurements. The benchmark tables below show the available evidence without filling missing axes.

Claude Opus 4.5GPT-5.6 Terra

AA-Omniscience AccuracyOverall. Higher is better. No documented setup difference

Claude Opus 4.540.9%

GPT-5.6 Terra36.8%

AA-Omniscience Hallucination RateOverall. Lower is better. No documented setup difference

Claude Opus 4.576.2%

GPT-5.6 Terra95.0%

CorpFin v2Overall. Higher is better. Test setup not documented as identical

Claude Opus 4.561.305 %

GPT-5.6 Terra65.307 %

GPQA DiamondOverall. Higher is better. Test setup not documented as identical

Claude Opus 4.579.546 %

GPT-5.6 Terra90.909 %

LegalBenchOverall. Higher is better. Test setup not documented as identical

Claude Opus 4.582.837 %

GPT-5.6 Terra85.105 %

LiveCodeBench v6Overall. Higher is better. Test setup not documented as identical

Claude Opus 4.575.034 %

GPT-5.6 Terra85.93 %

MedCodeOverall. Higher is better. Test setup not documented as identical

Claude Opus 4.545.174 %

GPT-5.6 Terra43.414 %

MedScribeOverall. Higher is better. Test setup not documented as identical

Claude Opus 4.583.246 %

GPT-5.6 Terra82.869 %

MMLU-ProOverall. Higher is better. Test setup not documented as identical

Claude Opus 4.585.59 %

GPT-5.6 Terra86.659 %

MMMU-ProOverall. Higher is better. No documented setup difference

Claude Opus 4.571.2%

GPT-5.6 Terra66.7%

MMMU-ProOverall. Higher is better. Test setup not documented as identical

Claude Opus 4.581.098 %

GPT-5.6 Terra86.474 %

MortgageTaxOverall. Higher is better. Test setup not documented as identical

Claude Opus 4.568.68 %

GPT-5.6 Terra67.329 %

Key to the marks:better valuebetter, but not conclusivetie

Benchmark scores for Claude Opus 4.5 and GPT-5.6 Terra
Benchmark and task	Claude Opus 4.5	GPT-5.6 Terra	Source
AA-Omniscience AccuracyOverall Test details No documented difference in the test setupVersion: AA Omniscience diagnosticMetric: AA-Omniscience AccuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: Claude Opus 4.5 (Non-reasoning), Reasoning: Non-reasoning, Attempts: AA-reported aggregate; diagnostic-specific run count is not stated on the leaderboard GPT-5.6 Terra: Snapshot: GPT-5.6 Terra (Non-reasoning), Reasoning: Non-reasoning, Attempts: AA-reported aggregate; diagnostic-specific run count is not stated on the leaderboardClaude Opus 4.5: Exact AA configuration: Claude Opus 4.5 (Non-reasoning) (release claude-opus-4-5, row claude-opus-4-5, UUID 4077490a-bbfb-404e-979a-a97a20e3b5de, reasoning=false, source reasoning-token configuration budget=0, suffix=Non-reasoning). This configured value is not measured token consumption. Proportion of all questions answered correctly, regardless of whether the model answers or abstains on other questions.GPT-5.6 Terra: Exact AA configuration: GPT-5.6 Terra (Non-reasoning) (release gpt-5-6-terra, row gpt-5-6-terra-non-reasoning, UUID 9b97a35e-6ac7-44d9-91c6-422fa678963e, reasoning=false, source reasoning-token configuration budget=0, suffix=Non-reasoning). This configured value is not measured token consumption. Proportion of all questions answered correctly, regardless of whether the model answers or abstains on other questions.	Winner40.9% This is the separately published accuracy diagnostic, not the AA-Omniscience Index. AA identifies higher values as better.	36.8% This is the separately published accuracy diagnostic, not the AA-Omniscience Index. AA identifies higher values as better.	Artificial Analysis Source details Data as of: 10/19/2026
AA-Omniscience Hallucination RateOverall Test details No documented difference in the test setupVersion: AA Omniscience diagnosticMetric: AA-Omniscience Hallucination RateScoring: Lower is betterClaude Opus 4.5: Snapshot: Claude Opus 4.5 (Non-reasoning), Reasoning: Non-reasoning, Attempts: AA-reported aggregate; diagnostic-specific run count is not stated on the leaderboard GPT-5.6 Terra: Snapshot: GPT-5.6 Terra (Non-reasoning), Reasoning: Non-reasoning, Attempts: AA-reported aggregate; diagnostic-specific run count is not stated on the leaderboardClaude Opus 4.5: Exact AA configuration: Claude Opus 4.5 (Non-reasoning) (release claude-opus-4-5, row claude-opus-4-5, UUID 4077490a-bbfb-404e-979a-a97a20e3b5de, reasoning=false, source reasoning-token configuration budget=0, suffix=Non-reasoning). This configured value is not measured token consumption. Proportion of incorrect answers among all non-correct responses: incorrect / (incorrect + partial answers + not attempted).GPT-5.6 Terra: Exact AA configuration: GPT-5.6 Terra (Non-reasoning) (release gpt-5-6-terra, row gpt-5-6-terra-non-reasoning, UUID 9b97a35e-6ac7-44d9-91c6-422fa678963e, reasoning=false, source reasoning-token configuration budget=0, suffix=Non-reasoning). This configured value is not measured token consumption. Proportion of incorrect answers among all non-correct responses: incorrect / (incorrect + partial answers + not attempted).	Winner76.2% This is the separately published hallucination-rate diagnostic, not the AA-Omniscience Index. AA identifies lower values as better.	95.0% This is the separately published hallucination-rate diagnostic, not the AA-Omniscience Index. AA identifies lower values as better.	Artificial Analysis Source details Data as of: 10/19/2026
CorpFin v2Overall Test details Test setup not documented as identicalNo direct winnerVersion: 2Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	61.305 %	Higher measured value65.307 %	Vals AI Source details Data as of: 08/12/2026
GPQA DiamondOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	79.546 %	Higher measured value90.909 %	Vals AI Source details Data as of: 09/01/2026
LegalBenchOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	82.837 %	Higher measured value85.105 %	Vals AI Source details Data as of: 10/13/2026
LiveCodeBench v6Overall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	75.034 %	Higher measured value85.93 %	Vals AI Source details Data as of: 09/01/2026
MedCodeOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 30,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 30,000 tokens	Higher measured value45.174 %	43.414 %	Vals AI Source details Data as of: 10/13/2026
MedScribeOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 30,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 30,000 tokens	Higher measured value83.246 %	82.869 %	Vals AI Source details Data as of: 10/13/2026
MMLU-ProOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	85.59 %	Higher measured value86.659 %	Vals AI Source details Data as of: 09/01/2026
MMMU-ProOverall Test details No documented difference in the test setupVersion: AA cohort: 1,730 questionsMetric: pass@1 accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: Claude Opus 4.5 (Non-reasoning), Reasoning: Non-reasoning, Attempts: pass@1, one run per question GPT-5.6 Terra: Snapshot: GPT-5.6 Terra (Non-reasoning), Reasoning: Non-reasoning, Attempts: pass@1, one run per questionClaude Opus 4.5: Exact AA configuration: Claude Opus 4.5 (Non-reasoning) (release claude-opus-4-5, row claude-opus-4-5, UUID 4077490a-bbfb-404e-979a-a97a20e3b5de, reasoning=false, source reasoning-token configuration budget=0, suffix=Non-reasoning). This configured value is not measured token consumption. The AA run covers 1,730 questions with ten answer options. Answers are extracted by regex and scored pass@1.GPT-5.6 Terra: Exact AA configuration: GPT-5.6 Terra (Non-reasoning) (release gpt-5-6-terra, row gpt-5-6-terra-non-reasoning, UUID 9b97a35e-6ac7-44d9-91c6-422fa678963e, reasoning=false, source reasoning-token configuration budget=0, suffix=Non-reasoning). This configured value is not measured token consumption. The AA run covers 1,730 questions with ten answer options. Answers are extracted by regex and scored pass@1.	Winner71.2% The benchmark page describes 3,460 questions in the full MMMU-Pro dataset; AA's methodology specifies a 1,730-question run.	66.7% The benchmark page describes 3,460 questions in the full MMMU-Pro dataset; AA's methodology specifies a 1,730-question run.	Artificial Analysis Source details Data as of: 10/19/2026
MMMU-ProOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	81.098 %	Higher measured value86.474 %	Vals AI Source details Data as of: 09/01/2026
MortgageTaxOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	Higher measured value68.68 %	67.329 %	Vals AI Source details Data as of: 09/01/2026
SAGEOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 30,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 30,000 tokens	45.002 %	Higher measured value47.003 %	Vals AI Source details Data as of: 10/08/2026
TaxEval v2Overall Test details Test setup not documented as identicalNo direct winnerVersion: 2Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	74.325 %	Higher measured value76.166 %	Vals AI Source details Data as of: 09/01/2026
CorpFin v2Exact Pages Test details Test setup not documented as identicalNo direct winnerVersion: 2Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	60.839 %	Higher measured value63.17 %	Vals AI Source details Data as of: 08/12/2026
GPQA DiamondFew-Shot CoT Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	79.293 %	Higher measured value89.899 %	Vals AI Source details Data as of: 09/01/2026
LegalBenchConclusion Tasks Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	87.7 %	Higher measured value90.327 %	Vals AI Source details Data as of: 10/13/2026
LiveCodeBench v6Easy Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	Higher measured value99.068 %	97.205 %	Vals AI Source details Data as of: 09/01/2026
MMLU-ProBiology Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	Higher measured value94.003 %	93.026 %	Vals AI Source details Data as of: 09/01/2026
MortgageTaxNumerical Extraction Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	Higher measured value77.424 %	74.324 %	Vals AI Source details Data as of: 09/01/2026
SAGEAutomata Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 30,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 30,000 tokens	29.365 %	Higher measured value38.889 %	Vals AI Source details Data as of: 10/08/2026
TaxEval v2Correctness Test details Test setup not documented as identicalNo direct winnerVersion: 2Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	63.123 %	Higher measured value65.822 %	Vals AI Source details Data as of: 09/01/2026
CorpFin v2Max Fitting Context Test details Test setup not documented as identicalNo direct winnerVersion: 2Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	60.723 %	Higher measured value66.317 %	Vals AI Source details Data as of: 08/12/2026
GPQA DiamondZero-Shot CoT Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	79.798 %	Higher measured value91.919 %	Vals AI Source details Data as of: 09/01/2026
LegalBenchInterpretation Tasks Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	82.235 %	Higher measured value83.178 %	Vals AI Source details Data as of: 10/13/2026
LiveCodeBench v6Hard Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	44.571 %	Higher measured value72.857 %	Vals AI Source details Data as of: 09/01/2026
MMLU-ProBusiness Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	80.862 %	Higher measured value90.875 %	Vals AI Source details Data as of: 09/01/2026
MortgageTaxSemantic Extraction Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	59.936 %	Higher measured value60.334 %	Vals AI Source details Data as of: 09/01/2026
SAGECalculus Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Temperature: 1, Output limit: 30,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 30,000 tokens	58.333 %	Higher measured value59.259 %	Vals AI Source details Data as of: 10/08/2026
TaxEval v2Stepwise Reasoning Test details Test setup not documented as identicalNo direct winnerVersion: 2Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	85.527 %	Higher measured value86.509 %	Vals AI Source details Data as of: 09/01/2026
CorpFin v2Shared Max Context Test details Test setup not documented as identicalNo direct winnerVersion: 2Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	62.354 %	Higher measured value66.434 %	Vals AI Source details Data as of: 08/12/2026
LegalBenchIssue Tasks Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	84.152 %	Higher measured value89.392 %	Vals AI Source details Data as of: 10/13/2026
LiveCodeBench v6Medium Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	81.462 %	Higher measured value87.728 %	Vals AI Source details Data as of: 09/01/2026
MMLU-ProChemistry Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	89.488 %	Higher measured value90.194 %	Vals AI Source details Data as of: 09/01/2026
SAGELinear Algebra Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 30,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 30,000 tokens	Higher measured value64.372 %	64.025 %	Vals AI Source details Data as of: 10/08/2026
LegalBenchRhetoric Tasks Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	79.777 %	Higher measured value82.098 %	Vals AI Source details Data as of: 10/13/2026
MMLU-ProComputer Science Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	84.146 %	Higher measured value90.976 %	Vals AI Source details Data as of: 09/01/2026
SAGEPartial Differential Equations Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 30,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 30,000 tokens	Higher measured value41.27 %	38.095 %	Vals AI Source details Data as of: 10/08/2026
LegalBenchRule Tasks Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	80.32 %	Higher measured value80.528 %	Vals AI Source details Data as of: 10/13/2026
MMLU-ProEconomics Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	Higher measured value89.573 %	88.981 %	Vals AI Source details Data as of: 09/01/2026
MMLU-ProEngineering Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	76.161 %	Higher measured value82.869 %	Vals AI Source details Data as of: 09/01/2026
MMLU-ProHealth Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	Higher measured value83.985 %	82.763 %	Vals AI Source details Data as of: 09/01/2026
MMLU-ProHistory Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	78.478 %	Higher measured value79.528 %	Vals AI Source details Data as of: 09/01/2026
MMLU-ProLaw Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	Higher measured value78.292 %	74.387 %	Vals AI Source details Data as of: 09/01/2026
MMLU-ProMath Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	92.302 %	Higher measured value94.152 %	Vals AI Source details Data as of: 09/01/2026
MMLU-ProOthers Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	Higher measured value84.632 %	84.091 %	Vals AI Source details Data as of: 09/01/2026
MMLU-ProPhilosophy Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	Higher measured value87.776 %	83.968 %	Vals AI Source details Data as of: 09/01/2026
MMLU-ProPhysics Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	89.838 %	Higher measured value91.07 %	Vals AI Source details Data as of: 09/01/2026
MMLU-ProPsychology Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.5: Snapshot: claude-opus-4-5-20251101, Compute: high, Temperature: 1, Output limit: 64,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	Higher measured value88.722 %	86.341 %	Vals AI Source details Data as of: 09/01/2026
Key to the marks:better valuebetter, but not conclusivetie

Our model tests

Our tests

SVG short test

One SVG prompt and fixed output settings. Captures are shown only with 0 reported reasoning tokens or documented lack of reasoning controls. Identical test conditions do not make the models' internal compute identical.

Shared test round: 43b8c5c46830

Claude Opus 4.5

Unavailable in this round

GPT-5.6 Terra

Unavailable in this round

Earlier tests

Pelican on a bicycle

A community classic for free-form SVG drawing.

Claude Opus 4.5

Reasoning (requested): high

Current attempt

Run date: Oct 1, 2026
API provider: openrouter
Requested API model: anthropic/claude-opus-4.5
API model reported in response: anthropic/claude-opus-4.5
Reasoning setting: high
Pinned endpoint: Anthropic | anthropic/claude-4.5-opus-20251124
Temperature: Provider default
Token limit including reasoning: 8,192 tokens
Test protocol: community-visual-tests-v1
Technical checks: Passed, not a quality rating
Response time: 21.6 s

Visually reviewed. This individual test does not establish overall model quality.

GPT-5.6 Terra

Reasoning (requested): high

Current attempt

Run date: Sep 7, 2026
API provider: openrouter
Requested API model: openai/gpt-5.6-terra
API model reported in response: openai/gpt-5.6-terra
Reasoning setting: high
Pinned endpoint: OpenAI | openai/gpt-5.6-terra-20260709
Temperature: Provider default
Token limit including reasoning: 8,192 tokens
Test protocol: community-visual-tests-v1
Technical checks: Passed, not a quality rating
Response time: 64.6 s

Visually reviewed. This individual test does not establish overall model quality.

Prompt and test conditions

Generate an SVG of a pelican riding a bicycle

Token limit including reasoning: 8,192 tokens

Task origin (Simon Willison)

How to read this comparison

Winning one benchmark is not an overall verdict

Your workload, budget, and required context length matter most. A coding benchmark says little about visual understanding or agent performance.

The standard price table uses direct developer rates. The provider comparison labels OpenRouter endpoints, regions, and special tariffs separately.

Every result links to its measurement source and retrieval date. Labels distinguish vendor reports, official benchmark leaderboards, and independent evaluations. Disputed or archived results are excluded.

More matchups

Compare Claude Opus 4.5 and GPT-5.6 Terra with other leading models using the same data and benchmark logic.

View the complete LLM comparison

Claude Opus 4.5 vs. GPT-5.6 Terra

Change model selection

General specifications

API pricing compared

Benchmark index compared

Shared benchmarks

Capability profile from matched benchmarks

Our tests

SVG short test

Claude Opus 4.5

GPT-5.6 Terra

Pelican on a bicycle

Winning one benchmark is not an overall verdict

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