Claude Opus 4.8
Not tested yet
Head-to-head comparison
Claude Opus 4.8 vs. GPT-5.6 Luna
Compare published benchmark results from matching versions and cohorts, API pricing, and technical specifications. Any documented test setup differences remain visible.
- shared result series
- 1
- distinct benchmarks
- 1
- latest retrieval
- 2026-09-02
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Specifications
General specifications
Release date, availability, context window, architecture, and published parameter counts at a glance. Undisclosed details remain marked as unavailable.
| Attribute | Claude Opus 4.8 | GPT-5.6 Luna |
|---|---|---|
| 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.
| Price type | Claude Opus 4.8 | GPT-5.6 Luna |
|---|---|---|
| API input | $5 | $0.2 ≤272K / $0.4 >272K |
| API output | $25 | $1.2 ≤272K / $1.8 >272K |
| Cache read | $0.5 | $0.02 ≤272K / $0.04 >272K |
| Cache write (5 min.) | $6.25 | $0.25 ≤272K / $0.5 >272K |
| Cache write (1 hr.) | $10 | Not listed |
| Price verified | 07/30/2026 Source | 08/11/2026 Source |
Claude Opus 4.8GPT-5.6 Luna
API inputUSD per 1M tokens, base tier
Claude Opus 4.8$5
GPT-5.6 LunaLower price$0.2
API outputUSD per 1M tokens, base tier
Claude Opus 4.8$25
GPT-5.6 LunaLower price$1.2
Cache readUSD per 1M tokens, base tier
Claude Opus 4.8$0.5
GPT-5.6 LunaLower price$0.02
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.
| 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 | Source07/30/2026 |
| GPT-5.6 Luna | OpenAI | Direct from developerUp to 272,000 context tokens | $0.2 | $1.2 | Source08/11/2026 |
| OpenAI | Direct from developerAbove 272,000 context tokens | $0.4 | $1.8 | Source08/11/2026 | |
| Amazon Bedrock | Via OpenRouteramazon-bedrock/us-east-1 | $0.22 | $1.32 | Source09/12/2026 | |
| Azure | Via OpenRouterazure | $0.2 | $1.2 | Source09/12/2026 | |
| Azure | Via OpenRouterazure/eu | $0.22 | $1.32 | Source09/12/2026 | |
| Azure | Via OpenRouterazure/us | $0.22 | $1.32 | Source09/12/2026 | |
| OpenAI | Via OpenRouteropenai | $0.2 | $1.2 | Source09/12/2026 | |
| OpenAI | Via OpenRouteropenai/fast | $0.4 | $2.4 | Source09/12/2026 | |
| OpenAI | Via OpenRouteropenai/flex | Lowest listed price: $0.1 | Lowest listed price: $0.6 | Source09/12/2026 |
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.
Not enough directly matched categories for a reliable radar
Only 1 of at least 5 categories have comparable, direct model measurements. The benchmark tables below show the available evidence without filling missing axes.
Claude Opus 4.8GPT-5.6 Luna
BrowseCompOverall. Higher is better. No documented setup difference
Claude Opus 4.8Winner84.3 %
GPT-5.6 Luna83.3 %
Key to the marks:better valuebetter, but not conclusivetie
| Benchmark and task | Claude Opus 4.8 | GPT-5.6 Luna | Source |
|---|---|---|---|
BrowseCompOverallTest detailsNo documented difference in the test setupVersion: 1,266 tasksMetric: accuracyScoring: Higher is betterCross-vendor comparison table with browsing tools. Exact agent systems differ. | Winner84.3 % Editorial selection from the vendor table, not a complete extract of the comparison cohort. | 83.3 % Editorial selection from the vendor table, not a complete extract of the comparison cohort. | OpenAISource detailsData as of: 07/09/2026 |
Key to the marks:better valuebetter, but not conclusivetie | |||
Our model tests
Community tests you can inspect
Compare how the models respond to the same prompt. Each test shows the first attempt, with no subsequent fixes to the generated code. These results do not contribute to an overall score.
Pelican on a bicycle
A community classic for free-form SVG drawing.
GPT-5.6 Luna
First attempt
- Run date
- 7 Sept 2026
- API provider
- openrouter
- Requested API model
- openai/gpt-5.6-luna
- API model reported in response
- openai/gpt-5.6-luna
- Pinned endpoint
- OpenAI | openai/gpt-5.6-luna-20260709
- Reasoning setting
- high
- 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
- 49.9 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.
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