Head-to-head comparison

Claude Opus 4.8 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: 288
distinct benchmark metrics: 42
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 4.8 and GPT-5.6 Terra
Attribute	Claude Opus 4.8	GPT-5.6 Terra
Provider	Anthropic	OpenAI
Released	May 2026	Jul 9, 2026
Availability	Legacy	Active
Model type	Proprietary	Proprietary
Parameters	Not published	Not published
Architecture	Not published	Not published
Context window	1,000,000 tokens	1,050,000 tokens
Knowledge cutoff	January 2026	February 16, 2026
Technical sources	Model, Knowledge cutoff	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 4.8 and GPT-5.6 Terra
Price type	Claude Opus 4.8	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 4.8GPT-5.6 Terra

API inputUSD per 1M tokens, base tier

Claude Opus 4.8$5

GPT-5.6 Terra$2

API outputUSD per 1M tokens, base tier

Claude Opus 4.8$25

GPT-5.6 Terra$12

Cache readUSD per 1M tokens, base tier

Claude Opus 4.8$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.

No provider tariff for Claude Opus 4.8 is available in the stored OpenRouter snapshot. The official direct price is still shown.

Provider pricing for Claude Opus 4.8 and GPT-5.6 Terra
Model	Provider	Purchase route and tariff	Input per 1M tokens	Output per 1M tokens	Source
Claude Opus 4.8	Anthropic	Direct from developerStandard API	Lowest listed price: $5	Lowest listed price: $25	Source09/22/2026
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 4.8

Overall index

57.0tied

GPT-5.6 Terra

Overall index

52.1tied

Claude Opus 4.8 leads in 5 of 11 shared areas. 5 areas are tied.

Area	Claude Opus 4.8	GPT-5.6 Terra
Codingtied	55.3	61.3
Reasoningtied	46.2	56.6
Knowledge	65.6	29.3
Agentstied	56.7	61.8
General	45.3	63.6
Financetied	65.0	60.4
Legaltied	57.4	41.4
Health	67.8	40.3
Multimodal	55.0	47.7
Productivity	68.3	49.1
Education	71.1	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.

Claude Opus 4.8

GPT-5.6 Terra

Coding: 61.4 / 100 (1 benchmark family)

Reasoning: 96.2 / 96.1 (3 benchmark families)

Knowledge: 100 / 46.9 (1 benchmark family)

Agentic tasks: 91.8 / 100 (3 benchmark families)

Search: 96.3 / 100 (1 benchmark family)

General: 87.4 / 100 (1 benchmark family)

Overall: 99.7 / 91.2 (2 benchmark families)

14 matched rows from 12 benchmark families were considered. The radar shows 7 of 7 comparable categories.

Claude Opus 4.8GPT-5.6 Terra

AA-BriefcaseOverall. Higher is better. No documented setup difference

Claude Opus 4.81,321.43 elo

GPT-5.6 Terra1,334.22 elo

AA-LCROverall. Higher is better. No documented setup difference

Claude Opus 4.877.7%

GPT-5.6 Terra83.0%

AA-OmniscienceOverall. Higher is better. No documented setup difference

Claude Opus 4.828.75 points

GPT-5.6 Terra0.05 points

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

Claude Opus 4.848.8%

GPT-5.6 Terra46.8%

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

Claude Opus 4.839.3%

GPT-5.6 Terra87.9%

Artificial Analysis Intelligence IndexOverall. Higher is better. No documented setup difference

Claude Opus 4.841.79 points

GPT-5.6 Terra42.083 points

AutomationBench-AAOverall. Higher is better. No documented setup difference

Claude Opus 4.845.6%

GPT-5.6 Terra59.6%

BrowseCompOverall. Higher is better. No documented setup difference

Claude Opus 4.884.3 %

GPT-5.6 Terra87.5 %

Code MigrationOverall. Higher is better. Test setup not documented as identical

Claude Opus 4.847.25 %

GPT-5.6 Terra47.804 %

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

Claude Opus 4.866.706 %

GPT-5.6 Terra65.307 %

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

Claude Opus 4.869.373 %

GPT-5.6 Terra66.205 %

Finance Agent (v2)Overall. Higher is better. Test setup not documented as identical

Claude Opus 4.853.918 %

GPT-5.6 Terra54.436 %

Key to the marks:better valuebetter, but not conclusivetie

Benchmark scores for Claude Opus 4.8 and GPT-5.6 Terra
Benchmark and task	Claude Opus 4.8	GPT-5.6 Terra	Source
AA-BriefcaseOverall Test details No documented difference in the test setupVersion: v1.1Metric: AA-Briefcase EloScoring: Higher is betterClaude Opus 4.8: Snapshot: Claude Opus 4.8 (Max), Reasoning: Max GPT-5.6 Terra: Snapshot: GPT-5.6 Terra (Max), Reasoning: MaxClaude Opus 4.8: Exact AA configuration: Claude Opus 4.8 (Max) (release claude-opus-4-8, row claude-opus-4-8, UUID 992b7b84-5069-4c6a-9295-834252553d50, reasoning=true, source reasoning-token configuration budget=0, suffix=Max). This configured value is not measured token consumption.GPT-5.6 Terra: Exact AA configuration: GPT-5.6 Terra (Max) (release gpt-5-6-terra, row gpt-5-6-terra, UUID bcf8db0a-3bb6-4d82-9516-0f57370c85a6, reasoning=true, source reasoning-token configuration budget=0, suffix=Max). This configured value is not measured token consumption.	1,321.43 elo	Winner1,334.22 elo	Artificial Analysis Source details Data as of: 10/19/2026
AA-LCROverall Test details No documented difference in the test setupVersion: v1.1Metric: Pass rateScoring: Higher is betterClaude Opus 4.8: Snapshot: Claude Opus 4.8 (Max), Reasoning: Max GPT-5.6 Terra: Snapshot: GPT-5.6 Terra (Max), Reasoning: MaxClaude Opus 4.8: Exact AA configuration: Claude Opus 4.8 (Max) (release claude-opus-4-8, row claude-opus-4-8, UUID 992b7b84-5069-4c6a-9295-834252553d50, reasoning=true, source reasoning-token configuration budget=0, suffix=Max). This configured value is not measured token consumption.GPT-5.6 Terra: Exact AA configuration: GPT-5.6 Terra (Max) (release gpt-5-6-terra, row gpt-5-6-terra, UUID bcf8db0a-3bb6-4d82-9516-0f57370c85a6, reasoning=true, source reasoning-token configuration budget=0, suffix=Max). This configured value is not measured token consumption.	77.7%	Winner83.0%	Artificial Analysis Source details Data as of: 10/19/2026
AA-OmniscienceOverall Test details No documented difference in the test setupVersion: unspecifiedMetric: AA-Omniscience IndexScoring: Higher is betterClaude Opus 4.8: Snapshot: Claude Opus 4.8 (Max), Reasoning: Max GPT-5.6 Terra: Snapshot: GPT-5.6 Terra (Max), Reasoning: MaxClaude Opus 4.8: Exact AA configuration: Claude Opus 4.8 (Max) (release claude-opus-4-8, row claude-opus-4-8, UUID 992b7b84-5069-4c6a-9295-834252553d50, reasoning=true, source reasoning-token configuration budget=0, suffix=Max). This configured value is not measured token consumption.GPT-5.6 Terra: Exact AA configuration: GPT-5.6 Terra (Max) (release gpt-5-6-terra, row gpt-5-6-terra, UUID bcf8db0a-3bb6-4d82-9516-0f57370c85a6, reasoning=true, source reasoning-token configuration budget=0, suffix=Max). This configured value is not measured token consumption.	Winner28.75 points The index can be negative and ranges from -100 to 100 according to Artificial Analysis.	0.05 points The index can be negative and ranges from -100 to 100 according to Artificial Analysis.	Artificial Analysis Source details Data as of: 10/19/2026
AA-Omniscience AccuracyOverall Test details No documented difference in the test setupVersion: AA Omniscience diagnosticMetric: AA-Omniscience AccuracyScoring: Higher is betterClaude Opus 4.8: Snapshot: Claude Opus 4.8 (Max), Reasoning: Max, Attempts: AA-reported aggregate; diagnostic-specific run count is not stated on the leaderboard GPT-5.6 Terra: Snapshot: GPT-5.6 Terra (Max), Reasoning: Max, Attempts: AA-reported aggregate; diagnostic-specific run count is not stated on the leaderboardClaude Opus 4.8: Exact AA configuration: Claude Opus 4.8 (Max) (release claude-opus-4-8, row claude-opus-4-8, UUID 992b7b84-5069-4c6a-9295-834252553d50, reasoning=true, source reasoning-token configuration budget=0, suffix=Max). 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 (Max) (release gpt-5-6-terra, row gpt-5-6-terra, UUID bcf8db0a-3bb6-4d82-9516-0f57370c85a6, reasoning=true, source reasoning-token configuration budget=0, suffix=Max). 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.	Winner48.8% This is the separately published accuracy diagnostic, not the AA-Omniscience Index. AA identifies higher values as better.	46.8% 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 4.8: Snapshot: Claude Opus 4.8 (Max), Reasoning: Max, Attempts: AA-reported aggregate; diagnostic-specific run count is not stated on the leaderboard GPT-5.6 Terra: Snapshot: GPT-5.6 Terra (Max), Reasoning: Max, Attempts: AA-reported aggregate; diagnostic-specific run count is not stated on the leaderboardClaude Opus 4.8: Exact AA configuration: Claude Opus 4.8 (Max) (release claude-opus-4-8, row claude-opus-4-8, UUID 992b7b84-5069-4c6a-9295-834252553d50, reasoning=true, source reasoning-token configuration budget=0, suffix=Max). 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 (Max) (release gpt-5-6-terra, row gpt-5-6-terra, UUID bcf8db0a-3bb6-4d82-9516-0f57370c85a6, reasoning=true, source reasoning-token configuration budget=0, suffix=Max). This configured value is not measured token consumption. Proportion of incorrect answers among all non-correct responses: incorrect / (incorrect + partial answers + not attempted).	Winner39.3% This is the separately published hallucination-rate diagnostic, not the AA-Omniscience Index. AA identifies lower values as better.	87.9% 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
Artificial Analysis Intelligence IndexOverall Test details No documented difference in the test setupVersion: v4.3.2Metric: Artificial Analysis Intelligence IndexScoring: Higher is betterClaude Opus 4.8: Snapshot: Claude Opus 4.8 (Max), Reasoning: Max GPT-5.6 Terra: Snapshot: GPT-5.6 Terra (Max), Reasoning: MaxClaude Opus 4.8: Exact AA configuration: Claude Opus 4.8 (Max) (release claude-opus-4-8, row claude-opus-4-8, UUID 992b7b84-5069-4c6a-9295-834252553d50, reasoning=true, source reasoning-token configuration budget=0, suffix=Max). This configured value is not measured token consumption.GPT-5.6 Terra: Exact AA configuration: GPT-5.6 Terra (Max) (release gpt-5-6-terra, row gpt-5-6-terra, UUID bcf8db0a-3bb6-4d82-9516-0f57370c85a6, reasoning=true, source reasoning-token configuration budget=0, suffix=Max). This configured value is not measured token consumption.	41.79 points	Winner42.083 points	Artificial Analysis Source details Data as of: 10/19/2026
AutomationBench-AAOverall Test details No documented difference in the test setupVersion: unspecifiedMetric: Objectives completed without guardrail violationsScoring: Higher is betterClaude Opus 4.8: Snapshot: Claude Opus 4.8 (Max), Reasoning: Max GPT-5.6 Terra: Snapshot: GPT-5.6 Terra (Max), Reasoning: MaxClaude Opus 4.8: Exact AA configuration: Claude Opus 4.8 (Max) (release claude-opus-4-8, row claude-opus-4-8, UUID 992b7b84-5069-4c6a-9295-834252553d50, reasoning=true, source reasoning-token configuration budget=0, suffix=Max). This configured value is not measured token consumption.GPT-5.6 Terra: Exact AA configuration: GPT-5.6 Terra (Max) (release gpt-5-6-terra, row gpt-5-6-terra, UUID bcf8db0a-3bb6-4d82-9516-0f57370c85a6, reasoning=true, source reasoning-token configuration budget=0, suffix=Max). This configured value is not measured token consumption.	45.6%	Winner59.6%	Artificial Analysis Source details Data as of: 10/19/2026
BrowseCompOverall Test details No documented difference in the test setupVersion: 1,266 tasksMetric: accuracyScoring: Higher is betterCross-vendor comparison table with browsing tools. Exact agent systems differ.	84.3 % Editorial selection from the vendor table, not a complete extract of the comparison cohort.	Winner87.5 % Editorial selection from the vendor table, not a complete extract of the comparison cohort.	OpenAI Source details Data as of: 07/09/2026
Code MigrationOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	47.25 %	Higher measured value47.804 %	Vals AI Source details Data as of: 10/12/2026
CorpFin v2Overall Test details Test setup not documented as identicalNo direct winnerVersion: 2Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	Higher measured value66.706 %	65.307 %	Vals AI Source details Data as of: 08/12/2026
EMBOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	Higher measured value69.373 %	66.205 %	Vals AI Source details Data as of: 10/12/2026
Finance Agent (v2)Overall Test details Test setup not documented as identicalNo direct winnerVersion: 2Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	53.918 %	Higher measured value54.436 %	Vals AI Source details Data as of: 10/12/2026
GDP.pdfOverall Test details No documented difference in the test setupVersion: unspecifiedMetric: All-pass rateScoring: Higher is betterClaude Opus 4.8: Snapshot: Claude Opus 4.8 (Max), Reasoning: Max GPT-5.6 Terra: Snapshot: GPT-5.6 Terra (Max), Reasoning: MaxClaude Opus 4.8: Exact AA configuration: Claude Opus 4.8 (Max) (release claude-opus-4-8, row claude-opus-4-8, UUID 992b7b84-5069-4c6a-9295-834252553d50, reasoning=true, source reasoning-token configuration budget=0, suffix=Max). This configured value is not measured token consumption.GPT-5.6 Terra: Exact AA configuration: GPT-5.6 Terra (Max) (release gpt-5-6-terra, row gpt-5-6-terra, UUID bcf8db0a-3bb6-4d82-9516-0f57370c85a6, reasoning=true, source reasoning-token configuration budget=0, suffix=Max). This configured value is not measured token consumption.	22.8%	Winner24.0%	Artificial Analysis Source details Data as of: 10/19/2026
GDPval-AAOverall Test details No documented difference in the test setupVersion: v2.1Metric: GDPval-AA EloScoring: Higher is betterClaude Opus 4.8: Snapshot: Claude Opus 4.8 (Max), Reasoning: Max GPT-5.6 Terra: Snapshot: GPT-5.6 Terra (Max), Reasoning: MaxClaude Opus 4.8: Exact AA configuration: Claude Opus 4.8 (Max) (release claude-opus-4-8, row claude-opus-4-8, UUID 992b7b84-5069-4c6a-9295-834252553d50, reasoning=true, source reasoning-token configuration budget=0, suffix=Max). This configured value is not measured token consumption.GPT-5.6 Terra: Exact AA configuration: GPT-5.6 Terra (Max) (release gpt-5-6-terra, row gpt-5-6-terra, UUID bcf8db0a-3bb6-4d82-9516-0f57370c85a6, reasoning=true, source reasoning-token configuration budget=0, suffix=Max). This configured value is not measured token consumption.	Winner1,453.47 elo	1,451.58 elo	Artificial Analysis Source details Data as of: 10/19/2026
GPQA DiamondOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	Higher measured value92.424 %	90.909 %	Vals AI Source details Data as of: 09/01/2026
Harvey's Legal Agent BenchmarkOverall · Task fully resolved Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: task resolution rateScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	Higher measured value9.583 %	0.833 %	Vals AI Source details Data as of: 10/12/2026
Humanity's Last ExamOverall Test details No documented difference in the test setupVersion: unspecifiedMetric: Text-only pass@1 accuracyScoring: Higher is betterClaude Opus 4.8: Snapshot: Claude Opus 4.8 (Max), Reasoning: Max GPT-5.6 Terra: Snapshot: GPT-5.6 Terra (Max), Reasoning: MaxClaude Opus 4.8: Exact AA configuration: Claude Opus 4.8 (Max) (release claude-opus-4-8, row claude-opus-4-8, UUID 992b7b84-5069-4c6a-9295-834252553d50, reasoning=true, source reasoning-token configuration budget=0, suffix=Max). This configured value is not measured token consumption.GPT-5.6 Terra: Exact AA configuration: GPT-5.6 Terra (Max) (release gpt-5-6-terra, row gpt-5-6-terra, UUID bcf8db0a-3bb6-4d82-9516-0f57370c85a6, reasoning=true, source reasoning-token configuration budget=0, suffix=Max). This configured value is not measured token consumption.	Winner48.7% Artificial Analysis describes this comparable run as 2,158 text-only questions, not the full 2,500-question dataset.	42.9% Artificial Analysis describes this comparable run as 2,158 text-only questions, not the full 2,500-question dataset.	Artificial Analysis Source details Data as of: 10/19/2026
IFBenchOverall Test details No documented difference in the test setupVersion: AA test set: 294 questionsMetric: IFBench prompt-level loose accuracy (pass@1)Scoring: Higher is betterClaude Opus 4.8: Snapshot: Claude Opus 4.8 (Max), Reasoning: Max, Attempts: pass@1, 5 repeats per question GPT-5.6 Terra: Snapshot: GPT-5.6 Terra (Max), Reasoning: Max, Attempts: pass@1, 5 repeats per questionClaude Opus 4.8: Exact AA configuration: Claude Opus 4.8 (Max) (release claude-opus-4-8, row claude-opus-4-8, UUID 992b7b84-5069-4c6a-9295-834252553d50, reasoning=true, source reasoning-token configuration budget=0, suffix=Max). This configured value is not measured token consumption. Artificial Analysis runs 294 questions from the IFBench test set with five repeats per question. The official evaluator scores prompt-level accuracy in loose mode as pass@1.GPT-5.6 Terra: Exact AA configuration: GPT-5.6 Terra (Max) (release gpt-5-6-terra, row gpt-5-6-terra, UUID bcf8db0a-3bb6-4d82-9516-0f57370c85a6, reasoning=true, source reasoning-token configuration budget=0, suffix=Max). This configured value is not measured token consumption. Artificial Analysis runs 294 questions from the IFBench test set with five repeats per question. The official evaluator scores prompt-level accuracy in loose mode as pass@1.	62.2% The often cited 58 refers to verifiable out-of-domain constraint types, not the number of questions in AA's test run.	Winner71.2% The often cited 58 refers to verifiable out-of-domain constraint types, not the number of questions in AA's test run.	Artificial Analysis Source details Data as of: 10/19/2026
Legal Research BenchOverall · All-pass Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: all-pass rateScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	Higher measured value43.75 %	41.346 %	Vals AI Source details Data as of: 10/12/2026
LegalBenchOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	83.568 %	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 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	Higher measured value87.819 %	85.93 %	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 betterClaude Opus 4.8: Snapshot: claude-opus-4-8, Harness: Arena Text, style control GPT-5.6 Terra: Snapshot: gpt-5.6-terra-xhigh, Reasoning: xhigh, Harness: Arena Text, style controlClaude Opus 4.8: Arena rating from 65,172 published pairwise votes.GPT-5.6 Terra: Arena rating from 43,271 published pairwise votes.	Higher measured value1,474.319 95% confidence interval: ±3.846The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	1,466.429 95% confidence interval: ±4.257The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	LMArena Source details Data as of: 10/15/2026
LMArena Vision, Style ControlOverall Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterClaude Opus 4.8: Snapshot: claude-opus-4-8, Harness: Arena Vision, style control GPT-5.6 Terra: Snapshot: gpt-5.6-terra-xhigh, Reasoning: xhigh, Harness: Arena Vision, style controlClaude Opus 4.8: Arena rating from 18,852 published pairwise votes.GPT-5.6 Terra: Arena rating from 11,020 published pairwise votes.	Higher measured value1,278.955 95% confidence interval: ±6.534The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	1,268.044 95% confidence interval: ±7.452The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	LMArena Source details Data as of: 10/09/2026
MedCodeOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 30,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 30,000 tokens	Higher measured value53.217 %	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 4.8: Compute: max, Temperature: 1, Output limit: 30,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 30,000 tokens	Higher measured value85.755 %	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 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	Higher measured value89.585 %	86.659 %	Vals AI Source details Data as of: 09/01/2026
MMMU-ProOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	Higher measured value86.59 %	86.474 %	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 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	Higher measured value69.912 %	67.329 %	Vals AI Source details Data as of: 09/01/2026
ProgramBenchOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: fully resolved rateScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	Higher measured value1 %	0.5 %	Vals AI Source details Data as of: 10/12/2026
Public Benefits Bench v1.1Overall Test details Test setup not documented as identicalNo direct winnerVersion: 1.1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	Higher measured value68.133 %	62.382 %	Vals AI Source details Data as of: 10/12/2026
SAGEOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 30,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 30,000 tokens	Higher measured value54.788 %	47.003 %	Vals AI Source details Data as of: 10/08/2026
SkillsBenchOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Harness: OpenHands, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: max, Harness: OpenHands, Output limit: 128,000 tokens	Higher measured value59.227 %	58.895 %	Vals AI Source details Data as of: 09/27/2026
SWE-bench VerifiedOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	88.6 %	Higher measured value95.4 %	Vals AI Source details Data as of: 09/01/2026
Tax Agent BenchOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	29.999 %	Higher measured value30.035 %	Vals AI Source details Data as of: 10/12/2026
TaxEval v2Overall Test details Test setup not documented as identicalNo direct winnerVersion: 2Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	75.634 %	Higher measured value76.166 %	Vals AI Source details Data as of: 09/01/2026
Terminal-BenchOverall Test details No documented difference in the test setupVersion: 4.0Metric: Task successScoring: Higher is betterClaude Opus 4.8: Snapshot: Claude Opus 4.8 (Max), Reasoning: Max GPT-5.6 Terra: Snapshot: GPT-5.6 Terra (Max), Reasoning: MaxClaude Opus 4.8: Exact AA configuration: Claude Opus 4.8 (Max) (release claude-opus-4-8, row claude-opus-4-8, UUID 992b7b84-5069-4c6a-9295-834252553d50, reasoning=true, source reasoning-token configuration budget=0, suffix=Max). This configured value is not measured token consumption.GPT-5.6 Terra: Exact AA configuration: GPT-5.6 Terra (Max) (release gpt-5-6-terra, row gpt-5-6-terra, UUID bcf8db0a-3bb6-4d82-9516-0f57370c85a6, reasoning=true, source reasoning-token configuration budget=0, suffix=Max). This configured value is not measured token consumption.	21.7%	Winner35.4%	Artificial Analysis Source details Data as of: 10/19/2026
Terminal-Bench 2.1Overall Test details Test setup not documented as identicalNo direct winnerVersion: 2.1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	71.91 %	Higher measured value77.528 %	Vals AI Source details Data as of: 09/28/2026
Terminal-Bench 4.0Overall Test details Test setup not documented as identicalNo direct winnerVersion: 4.0Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	Higher measured value23.232 %	22.727 %	Vals AI Source details Data as of: 10/13/2026
Terminal-Bench ScienceOverall Test details Test setup not documented as identicalNo direct winnerVersion: 0.1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Harness: Mini-SWE-agent, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: max, Harness: Mini-SWE-agent, Output limit: 128,000 tokens	4.286 %	Higher measured value10 %	Vals AI Source details Data as of: 10/14/2026
Vals IndexOverall Test details Test setup not documented as identicalNo direct winnerVersion: 2.1Metric: weighted index scoreScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	Higher measured value55.1 %	53.085 %	Vals AI Source details Data as of: 10/13/2026
Vals Multimodal IndexOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1.2Metric: weighted index scoreScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	Higher measured value70.889 %	65.07 %	Vals AI Source details Data as of: 08/11/2026
Vibe Code Bench v1.1Overall Test details Test setup not documented as identicalNo direct winnerVersion: 1.1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Harness: OpenHands, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: max, Harness: OpenHands, Output limit: 128,000 tokens	Higher measured value82.725 %	74.594 %	Vals AI Source details Data as of: 10/12/2026
Code MigrationCLI Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	40.143 %	Higher measured value40.405 %	Vals AI Source details Data as of: 10/12/2026
CorpFin v2Exact Pages Test details Test setup not documented as identicalNo direct winnerVersion: 2Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	Higher measured value64.336 %	63.17 %	Vals AI Source details Data as of: 08/12/2026
EMBComps Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	Higher measured value72.797 %	62.157 %	Vals AI Source details Data as of: 10/12/2026
Finance Agent (v2)Adjustments Test details Test setup not documented as identicalNo direct winnerVersion: 2Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	48.387 %	Higher measured value49.711 %	Vals AI Source details Data as of: 10/12/2026
GPQA DiamondFew-Shot CoT Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	Higher measured value91.919 %	89.899 %	Vals AI Source details Data as of: 09/01/2026
Harvey's Legal Agent BenchmarkAntitrust Competition · Criteria passed Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: criteria pass rateScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	Higher measured value87.319 %	77.536 %	Vals AI Source details Data as of: 10/12/2026
Legal Research BenchAdministrative / Regulatory · All-pass Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: all-pass rateScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	43.939 %	Higher measured value57.576 %	Vals AI Source details Data as of: 10/12/2026
LegalBenchConclusion Tasks Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	88.937 %	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 4.8: Compute: max, Temperature: 1, Output limit: 128,000 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
LMArena Text, Style ControlOverall Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterClaude Opus 4.8: Snapshot: claude-opus-4-8-high, Reasoning: high, Harness: Arena Text, style control GPT-5.6 Terra: Snapshot: gpt-5.6-terra-xhigh, Reasoning: xhigh, Harness: Arena Text, style controlClaude Opus 4.8: Arena rating from 64,100 published pairwise votes.GPT-5.6 Terra: Arena rating from 43,271 published pairwise votes.	Higher measured value1,481.495 95% confidence interval: ±3.868The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	1,466.429 95% confidence interval: ±4.257The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	LMArena Source details Data as of: 10/15/2026
LMArena Vision, Style ControlOverall Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterClaude Opus 4.8: Snapshot: claude-opus-4-8-high, Reasoning: high, Harness: Arena Vision, style control GPT-5.6 Terra: Snapshot: gpt-5.6-terra-xhigh, Reasoning: xhigh, Harness: Arena Vision, style controlClaude Opus 4.8: Arena rating from 18,341 published pairwise votes.GPT-5.6 Terra: Arena rating from 11,020 published pairwise votes.	Higher measured value1,285.632 95% confidence interval: ±6.5The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	1,268.044 95% confidence interval: ±7.452The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	LMArena Source details Data as of: 10/09/2026
MMLU-ProBiology Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	Higher measured value94.7 %	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 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	Higher measured value79.73 %	74.324 %	Vals AI Source details Data as of: 09/01/2026
ProgramBenchAlmost Resolved Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: almost-resolved rateScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	Higher measured value15.5 %	15 %	Vals AI Source details Data as of: 10/12/2026
SAGEAutomata Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 30,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 30,000 tokens	Higher measured value41.666 %	38.889 %	Vals AI Source details Data as of: 10/08/2026
SkillsBenchNo Skills Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Harness: OpenHands, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: max, Harness: OpenHands, Output limit: 128,000 tokens	43.674 %	Higher measured value48.842 %	Vals AI Source details Data as of: 09/27/2026
SWE-bench Verified<15 min fix Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	92.784 %	Higher measured value96.907 %	Vals AI Source details Data as of: 09/01/2026
Tax Agent BenchControversy & Precedence Analysis Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	13.133 %	Higher measured value16.667 %	Vals AI Source details Data as of: 10/12/2026
TaxEval v2Correctness Test details Test setup not documented as identicalNo direct winnerVersion: 2Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: xhigh, Output limit: 128,000 tokens	64.513 %	Higher measured value65.822 %	Vals AI Source details Data as of: 09/01/2026
Terminal-Bench 2.1Easy Test details Test setup not documented as identicalNo direct winnerVersion: 2.1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	No direct winner100 %	No direct winner100 %	Vals AI Source details Data as of: 09/28/2026
Terminal-Bench 4.0Hardware Test details Test setup not documented as identicalNo direct winnerVersion: 4.0Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: max, Output limit: 128,000 tokens	Higher measured value26.667 %	0 %	Vals AI Source details Data as of: 10/13/2026
Terminal-Bench ScienceEarth Sciences Test details Test setup not documented as identicalNo direct winnerVersion: 0.1Metric: accuracyScoring: Higher is betterClaude Opus 4.8: Compute: max, Harness: Mini-SWE-agent, Temperature: 1, Output limit: 128,000 tokens GPT-5.6 Terra: Reasoning: max, Harness: Mini-SWE-agent, Output limit: 128,000 tokens	No direct winner0 %	No direct winner0 %	Vals AI Source details Data as of: 10/14/2026
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 4.8

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 4.8

Reasoning (requested): high

Current attempt

Run date: Oct 1, 2026
API provider: openrouter
Requested API model: anthropic/claude-opus-4.8
API model reported in response: anthropic/claude-opus-4.8
Reasoning setting: high
Pinned endpoint: Anthropic | anthropic/claude-4.8-opus-20260528
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: 18 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 4.8 and GPT-5.6 Terra with other leading models using the same data and benchmark logic.

View the complete LLM comparison

Claude Opus 4.8 vs. GPT-5.6 Terra

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General specifications

API pricing compared

Benchmark index compared

Shared benchmarks

Capability profile from matched benchmarks

Our tests

SVG short test

Claude Opus 4.8

GPT-5.6 Terra

Pelican on a bicycle

Winning one benchmark is not an overall verdict

Related LLM comparisons