Head-to-head comparison
Claude Mythos 5 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.
1
shared result series
1
distinct benchmarks
2026-08-02
latest retrieval
Change model selection
Specifications and cost
General specifications and standard API pricing
Undisclosed parameter counts and knowledge cutoffs stay marked as unavailable. The table shows direct standard token pricing, including documented context tiers. Batch, fast, priority, regional surcharges, tool calls, and cloud platform pricing are excluded.
| Attribute | Claude Mythos 5 | GPT-5.6 Luna |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Released | Jun 9, 2026 | Jun 26, 2026 |
| Availability | Limited access | 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, Context, Knowledge cutoff | Model, Context, Knowledge cutoff |
| API pricing per 1M tokens | ||
| API input | $10 | $0.2 ≤272K / $0.4 >272K |
| API output | $50 | $1.2 ≤272K / $1.8 >272K |
| Cache read | $1 | $0.02 ≤272K / $0.04 >272K |
| Cache write (5 min.) | $12.5 | $0.25 ≤272K / $0.5 >272K |
| Cache write (1 hr.) | $20 | Not listed |
| Price verified | 07/30/2026Source | 08/11/2026Source |
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.
| Benchmark and task | Claude Mythos 5 | GPT-5.6 Luna | Comparability | Source |
|---|---|---|---|---|
| BrowseCompOverall | 88 %Winner 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. | 1,266 tasksaccuracyHigher is betterCohort: browsecomp-openai-gpt-5-6-tableNo documented setup differenceWinner: Claude Mythos 5Claude Mythos 5: No further settings disclosed GPT-5.6 Luna: No further settings disclosedCross-vendor comparison table with browsing tools. Exact agent systems differ. | OpenAIType: Vendor-reportedLeaderboard updated: 2026-07-09Import ID: curated-openai-2026-08-02-55280172a0ed / curated-openai-2026-08-02-65d8d2d5bbb4Retrieved 2026-08-02 |
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.
Prices use official API rates per 1M tokens. Web subscriptions and cloud platform surcharges can differ.
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
Related LLM comparisons
Compare Claude Mythos 5 and GPT-5.6 Luna with other leading models using the same data and benchmark logic.
View the complete LLM comparison